Team Fortress 2/WMG

A trophy taker.

 * Primary: Weak Gun
 * Melee: Weak Combat Knife
 * Secondary: You loot the corpse of an enemy within a certain range and are able to use its primary weapon.
 * So they get to keep the weapon for six seconds, or...
 * What purpose will this Trophy Taker serve?

A Zombie.

 * Valve will make "Zombie Fortress" official, but instead of being Heavy, Scouts and Spies be "Zombies", they'll actually make a proper Zombie class.

A Vehicle Operator
A female japanese character (thus defying two stereotypes) able to operate vehicles. She will only be available on certain maps designed for and with vehicles. She will not be praticularly durable, fast on foot or well armed (shotgun, pistol and a tire iron), but she can operate ATVs, armed motorcylces and boats under combat conditions (if others try to do so, they suffer and any passengers will hang on for dear life, being unable to fire out, they also kick the bucket if the vehicle is destroyed), vehicles she runs get more durability and she can use vehicle mounted weapons. While driving she can not capture points. The Engineer can repair her vehicles.

The Portalist

 * Chell's available now, isn't she? After going through twenty chambers of testing hell, she's probably got a few screws loose, which means she'd fit right in with the mercenaries. Two of her weapons would the ASHPD and combustible lemons. Her health would be very high to reflect her determinator status, but her attacks do not cause much damage. She would be best for defense, using the portal gun to teleport the rival team away (done by placing one portal somewhere on the map and firing the other underneath/at the other player). This was my friend's idea, I take no credit.
 * The first female TF2 class would probably shock the fanbase more than the Free-To-Play announcement...
 * Alternatively, instead of high health, she regenerates health really, really fast like in the Portal.
 * An alternate secondary weapon could be a small machine gun, built from the remains of a turret. It will still be activated, and will talk.
 * I get the feeling Chell would get the hell out of there as soon as she heard The Announcer's voice.
 * Who said it had to be Chell? Could just be some random Aperture volunteer.
 * She would need a splash of cartoon paint, and she helps the team idea with portals, but flamewars over how Chell Portals+ BONK, heavy/medic combo, Demospam, botomless pits, etc. would utterly ruin balance. Sounds like it would make a fun mod, however.

Assistant

 * A support class who gets assigned a person to protect, probably the least experienced person in their team. Has 130 health, and is a balanced-ish weak-ish class.
 * Increased stats if the person they're supposed to protect dies. Of course, they'll come up with something so you can't take advantage of it.

A Sentry Gun

 * This time, it has tank treads, allowing the gun to move. Has 150 health, medium speed, and can only fire. You could melee, yes, but it would require moving the mouse up.
 * Unlocking the Wrangler lets you kinda do this. You can't move, but you have an awesome deflector shield and can fire much quicker!
 * I still like the "sentry-has-tank-treads-but-it's-a-level-1" thing. I do have to mention that the Sentry can be healed (and ubercharged) by a Medic and repaired/refilled by Engineers and if the Sentry dies, it breaks into four pieces like a normal Sentry and gives 25 metal each piece.

An actually balanced class

 * He uses silly things like a selective-fire carbine (primary attack is a high-accuracy, medium-damage single shot, secondary is less-powerful, less accurate automatic fire)and has a ridiculous sidearm called a pistol(somewhere in power, range, accuracy, and firerate between the weapon of the same name and the spy's revolver). his melee weapon is a bleedout-causing, short-range but high-damage curiosity called a "combat knife". he has 185 health and medium damage.
 * Ugh, so, in other words, a class who's good at everything, bad at nothing, uses a melee weapon expressely designed to be annoying, and has more HP than the Demoman? Do not want.
 * No, a Boring but Practical class that uses weapons you would be likely to find in the '50's and isn't cripplingly overspecialized. The health can be lowered.
 * Impossible to balance considering the Heavy and Sniper are the only ones who can do any real sort of medium to far distance damage without being piddling or incredibly telegraphed. It would render the Heavy and Soldier redundant.
 * Also, completely doesn't fit the fun, silly attitude of team fortress; you yourself said it's boring. Practicality isn't necessarily the issue. And it doesn't fill any role that another class doesn't.
 * So, according to you, the tenth class is more or less the Soldier with an SMG?
 * The entire point of Team Fortress 2 is that no one class can be proficient in every situation. Every class has to have weaknesses and strengths to force you to work with your teammates.

Gunslinger

 * More specifically, a dual-revolver wielding who holds Guns Akimbo, a la Death The Kid.
 * Perfect for swatting down Scouts
 * Even better, he'll be the depressed deadpan snarker Blu Oni to the other classes' Red Oni
 * Possible taunt attack: pointing a gun at an enemy's mouth and growling "You make me sick. Die." That would be totally badass.
 * Deadpan snarking moments would include overcompensation jokes.

The Announcer

 * She got bored of watching, and decided to take part.
 * Her melee weapon would be the microphone she uses.
 * And she would have the ability to stun the enemy team by making a demoralizing comment.

The Strategist

 * A character based on careful planning and tricky moves.
 * Various attacks whould include out of place items, the use of newly discovered war machines like heat-seeking missiles and the ability to make the moves of the other classes backfire on them, such as being unable to trigger bombs or being able to see through spies. And also the ability to hide and disguise themselves as inanimate objects.
 * Most hated enemy of The Engineer. Building objects vs Scavenging and manipulating items.
 * The Character whould be of Irish heritage and have a mangled accent. Kicked out of military after being classed as 'offically insane' -- in reality has Aspergers Syndrome. A BIG Mood Swinger from Axe Crazy to The Wonka in a few seconds. Often can be naive and gets distracted easily. Originaly a Hikikimori and with a phobia of blood, took the job to help curve his fear. Will be Ambiguously Gay and a devote catholic. Often teams up with Spies or Scouts.
 * Appearance wise the character whould be a stereotypical Irish man. Red hair, green eyes, small/thin but strong and the love of beer. Rather lanky and frightenly pale. Age wise from 21 to 30 as he is obsessed with new world machines and recently got out of military school/boot camp/mental hospital. Wears a button-up shirt, combat trousers tucked into his black Wellington boots and a kaki green backpack.
 * Possible taunts
 * (to Scouts): Not really fast without your femur are yeh? Seriously, I think you were still running with out it.
 * (to Snipers): Next time : TRY RUNNING!
 * (to Heavys): I've eaten PIGS the size of you, you really think humans are an exception?
 * (to Spies): Work on your disguise next time!' or There goes the charming french devil!
 * (to Demomans): Get yer self a bloody second eye ya drunken pansy!
 * (to Medics): Where I came from - medicine men were burned as witches! along with HE'S A GERMAN WITCH, GET EM!
 * (to Soldiers): Take the helmet off, you'll see me trying to kill you!
 * (to Pyros): I cannae understand yer accent man.
 * (to Engieneers): I broke yer toys, Sorry! or Tá do mháthair an capall Meiriceánach fiáin! (meaning: Your mother is a wild american horse!)

A Squid
Spies will be perfect for being squids, since they're already Tentaspies.

A poison master.

 * The only class who cannot be seen by the enemy team (but you can see the one on your team just fine, He still takes damage when hit and actually has the lowest health of any class.) When you are hit by him (a poison dart is fired from a tranquilizer gun he calls it "a happy pill from his smile gun"), you get an initial 10 point health boost, but then your health begins to drain at a steady pace three seconds later. The more "darts" he gets into you, the faster you lose health. The only way to stop the poison is for a medic to heal you.
 * The character is a former hippie (With a totally radical accent) who discovered his devious streak when experimenting with various natural remedies. He still believes war is evil, so naturally he goes about killing off all "warmongers"... at least only the ones on the opposing team. He retains many hippie-like traits, such as an insistence on natural remedies and taunts relating to the opponent's horoscope, but actually appears as a rather clean-cut young man. May or may not smoke weed behind the barracks. All his weapons have euphemistical names such as "love bomb" (A mine he drops, you get damaged if you wander through its mist), "Smile gun", "soothing tea" which is actually acidic and also causes burns, or "Miss Caroline" (a spiky cactus melee weapon).
 * Alternately, he mostly has techniques and items that help your teammates survive (like a Jack of All Trades between the Medic, Engineer, and Demoman) and hinder the other team's ability to attack. He has an alternate tea that restores a smaller amount of health than the sandvich but eliminates bleedout effects, and has the Peace Offering Tranquilizer that slows the target's run speed and causes a (mild) Interface Screw/Screw (labelled P.O.T., with each letter pronounced to form a mispronounced, drawled-out "peyote"). One of his non-damaging taunts is threatening to chain himself to the front of a turret so it can't be used.

The Mann

 * Redmond or Blutarch Mann, depending on which team you're on.
 * Medium speed, moves around on a motorized desk/wheelchair combination, with a life support machine mounted on the back. His weapons are quite weak, for balancing reasons (see below).
 * Main feature of the class is his ability to regenerate health at an incredibly fast rate, thanks to his life support machine. Is almost impossible to kill, though can be slowed down. If his health goes to zero, he will die temporarily, then return to life ten seconds later unless his life support machine is destroyed.
 * The life support machine can also provide health for nearby teammates, similar to a dispenser.
 * Personality will be totally insane, perhaps senile, with delusions of godhood. Will often talk about death, and that he knows what's coming to the people he kills.
 * Will often reference the original mercenary team, perhaps believing the new team to be the originals.
 * Other team members may refer to him as 'boss'.

The Auxiliary

 * The one from the fanfic. In an attempt to be more useful, she'll also be able to reload sentries. (I know it won't happen. Get modding.)

The K9 Unit

 * (I know Valve already joked about this, but whatever) K9 was originally part of a small local police department from Florida. A team of scientists had privately asked many departments to allow their dogs to be observed and tested for a special project. K9 was one of the hundreds of dogs screened, and managed to make it to the final stage of the project, which was revealed to be an experiment to create a genetically-enhanced, humanly intelligent superdog for undisclosed purposes. Of the final thirty dogs, he was the only one to survive the process. With his new intelligence, he learned how to speak English and use man-made objects. He has been purchased for use in the war between RED and BLU. Ever since gaining his intelligence, he has shown a serious attitude and never tolerates goofing off. He seems to take great pleasure in not having to hold back against his opponents. He also displays a mistrust of all humans, due to a grudge he has held against his original partner for giving him up.
 * Info-
 * Name—Beau
 * Breed—German Shepherd
 * Job – Canine Assistance
 * Motto – “The bite is definitely worse than the bark.”
 * Type – Support
 * Speed – 124%
 * Health – 125 HP
 * Pros-
 * Can collect and carry ammo and health boxes to teammates (up to five items total at one time)
 * Can detect Spies (when cloaked, a Spy cannot be pinpointed, but K9 can alert teammates to a Spy’s presence; he can also sniff his teammates and discover a disguised Spy)
 * Can detect Sticky Bombs (like cloaked Spies, they cannot be pinpointed, but K9 can alert teammates to their presence)
 * Can push Payload carts at twice the rate of other classes, like Scout.
 * Cons-
 * Can capture control points, but only at half the rate of human classes (one-fourth the rate of Scout)
 * Cannot be Übercharged by a Medic
 * Weapons-
 * Primary – Shotgun (attached to harness on back)
 * Secondary – Shock Collar (collar that fires short-range electric pulses that slightly damage and temporarily stun enemies; requires recharge between uses)
 * Melee – Teeth
 * Taunts-
 * Primary – Looks around briefly, notices tail, and chases it for a moment, then realizes what he’s doing and shakes himself out of it
 * Secondary – Sits and begins scratching only to accidentally activate his collar and shock himself
 * Melee – Chuckles menacingly, lifts leg, and pees; if he successfully hits a target, he says, “Bet you really liked that little shower, didn’t ya?” and places the effects of Jarate on them for three seconds; cannot be used to reveal Spies or put out fires (not enough piss for that)
 * The tenth class could be one dog, K9, OR there could be three subclasses to the K9 Unit that all are specialized to support the team in a specific way. Together, they create their own new class category-Canine.

K9 Unit Fetch

 * (Yes, more-or-less reused backstories. Sue me.) Fetch originally belonged to a scientist from England. He worked on a team of scientists that observed and tested many dogs for a special project. He managed to get Fetch into screening, and she made it to the final stage of the project, an experiment to create a genetically-enhanced, humanly intelligent superdog for undisclosed purposes. Of the final thirty dogs, she was one of the only three to survive the process. She hated the testing and training she was put through and managed to escape the laboratory. She was found by a family, and lived there happily until she was sold for use in the war between RED and BLU. She has a rather happy-go-lucky attitude, and enjoys the company of others. She tends to stay away from combat, preferring to find items to help her human companions. Over the course of her service, she has become friends with most of the team, but is closest with Heavy and Demoman.
 * Info-
 * Name – Fetch
 * Breed – Labrador Retriever
 * Job – Searching and Gathering
 * Motto – “Ask, and I shall find!”
 * Type – Canine
 * Speed – 124%
 * Health – 125 HP
 * Pros-
 * Can collect and carry ammo and health boxes to teammates (up to six items total at one time)
 * Can carry one dropped weapon to a teammate to refill their ammo (does not take up a slot in carriage)
 * Can steal a non-melee weapon from an enemy (via a backstab-like move), causing them to lose that weapon until they resupply or respawn, unless they manage to retrieve their weapon from Fetch (cause her to drop it by killing her, stunning her, or attacking her with a critical hit); cannot steal a weapon if she is already carrying another
 * Her ability to carry ammo makes her a good companion for Heavies and Pyros, who chew up ammo very quickly, and Snipers, who often snipe from places with no nearby ammo or fallen weapons
 * Cons-
 * Can capture control points, but only at half the rate of human classes (one-fourth the rate of Scout)
 * Cannot be Übercharged by a Medic
 * Can attack and kill enemies, but combat is a very dangerous place for Fetch due to her fragility, and it is very easy for her to be killed if not in the hands of a capable player
 * Weapons-
 * Primary – Shotgun (attached to harness on back)
 * Secondary – Grabber (mechanical arm attached to harness used to steal from enemies and carry dropped weapons)
 * Melee – Teeth
 * Taunts-
 * Primary – Sits, pants, wags tail, and looks all-around cute
 * Secondary – Starts biting at the Grabber and it bops her on the nose, causing her to shout, “Hey!” or “Ow!”
 * Melee – Sniffs the ground and intently looks in the direction of the nearest ammo/health box; if there are none within range, she looks around and shuffles before returning to default stance

K9 Unit Hunter

 * Hunter originally worked as a security dog in a Virginia airport. A team of scientists had privately asked many departments to allow their dogs to be observed and tested for a special project. Hunter was one of the hundreds of dogs screened, and managed to make it to the final stage of the project, which was revealed to be an experiment to create a genetically-enhanced, humanly intelligent superdog for undisclosed purposes. Of the final thirty dogs, he was one of the only three to survive the process. He has been purchased for use in the war between RED and BLU. He has a laid-back attitude, and enjoys simply lying in the sun and napping. He doesn’t enjoy fighting, but is more than happy to assist his human companions with his nose. Over the course of his service, he has become friends with most of the team, but is closest with Engineer, Sniper, and Medic.
 * Info-
 * Name – Hunter
 * Breed – Bloodhound
 * Job – Detection and Signaling
 * Motto – “Nothing escapes this nose right here.”
 * Type – Canine
 * Speed – 107%
 * Health – 125 HP
 * Pros-
 * Can detect Spies (when cloaked, a Spy cannot be pinpointed, but Hunter can alert teammates to a Spy’s presence; he can also sniff his teammates and discover a disguised Spy)
 * Can detect Sticky Bombs (like cloaked Spies, they cannot be pinpointed, but Hunter can alert teammates to their presence)
 * Due to his ability to detect Stickies and Spies, Hunter is a good companion for Engineers and Snipers.
 * Whenever enemies are within a certain range of him (even behind obstacles such as walls), Hunter’s body posture changes to help warn teammates to an incoming attack
 * Cons-
 * Can capture control points, but only at half the rate of human classes (one-fourth the rate of Scout)
 * Cannot be Übercharged by a Medic
 * Can attack and kill enemies, but combat is a dangerous place for Hunter due to his fragility, and it is easy for him to be killed if not in the hands of a capable player
 * Weapons-
 * Primary – Shotgun (attached to harness on back)
 * Secondary – Steak (works like the Sandvich, i.e. restores health, puts out fires, and can be dropped)
 * Melee – Teeth
 * Taunts-
 * Primary – Looks up, pants, and wags tail; if a human teammate is in range, they will pet Hunter
 * Secondary – Sits, tosses the Steak up in the air, scratches himself, and then catches the falling Steak
 * Melee – Sniffs the ground and bays; if a Sticky is nearby, he shouts, “Sticky!” or “Stickies ahoy!” If a Spy is within range, he shouts, “Spy!”, “There’s a Spy here!”, or, “I smell Spies…!” If both are near, he shouts, “Be careful! I’m getting Stickies and Spies here.” If there is nothing around, he doesn’t bay and simply returns to his default stance

K9 Unit Digger

 * Digger originally belonged to a loving Canadian family, but was abandoned when they moved away. He was found by a scientist who worked on a team of scientists that observed and tested dogs for a special project. Digger was put into screening and managed to make it to the final stage of the project, an experiment to create a genetically-enhanced, humanly intelligent superdog for undisclosed purposes. Of the final thirty dogs, he was one of the only three to survive the process. He has been purchased for use in the war between RED and BLU. He is extremely hyperactive, and hates being bored more than anything else in the world. While he doesn’t actively engage in fighting, he highly enjoys digging giant holes that trap unsuspecting foes. Over the course of his service, he has become friends with most of the team, but is closest with Scout and Pyro.
 * Info-
 * Name – Digger
 * Breed – Airedale Terrier
 * Job – Trapping and Stalling
 * Motto – “Nobody out-digs me, eh!”
 * Type – Canine
 * Speed – 124%
 * Health – 125 HP
 * Pros-
 * Can dig holes to set traps for oncoming enemies, but only in certain places; if an enemy falls into the hole, they will be stuck there, unable to move or attack for five seconds
 * Can set up to three traps at one time
 * Digger’s hole traps can be quite effective when combined with a waiting Sentry or human attacker, such as Heavy
 * Cons-
 * Can capture control points, but only at half the rate of human classes (one-fourth the rate of Scout)
 * Cannot be Übercharged by a Medic
 * Can attack and kill enemies, but combat is a very dangerous place for Digger due to his fragility, and it is easy for him to be killed if not in the hands of a capable player
 * Weapons-
 * Primary – Shotgun (attached to harness on back) (forgive me for giving them all shotguns. I couldn't think of anything better. But they would all get special shotgun unlocks specific to them)
 * Secondary – Digging Laser (small laser attached to collar to assist in digging through hard surfaces and to damage close foes)
 * Melee – Teeth
 * Taunts-
 * Primary – Bounces around playfully while barking
 * Secondary – Tests his laser on the ground directly beneath him and starts pawing the ground; if he whines and doesn’t pull any dirt up, a trap can’t be set there; if he says, “Yeah! Yeah! Here’s the spot!” and dirt flies up, a trap can be set there
 * Melee – Prances about in a circle before crouching, jumping, and doing a flip
 * I had also thought of having an assistant dog for each class, made to help them specifically, but that would be too much. Even just the three is probably pushing it.
 * You'd probably only be allowed to use one of the K-9 Units at a time. All four of them could be on the field, but no duplicates of each.

The Suicide Bomber

 * His only weapon is the detonator for the TNT strapped to his chest.

The Saboteur

 * Character based on attacking strategic enemy choke points and disrupting their flow of battle.
 * Is of Creole descent, and used to lead a street racing ring in New Orleans. Took the job after his car was stolen. A little more pleasant than his teammates, despite his gang-banging past, but can get VERY eager to kill when the chips are down.
 * Weapons would include various landmines which confuse, impede, and otherwise screw up enemies. Basic mines are proximity explosives, others would create a smokescreen, slow down enemy movement (perhaps some kind of sticky goo that sprays out of the mine?) or cause a mild Interface Screw. Melee weapon would be a combat knife shaped like the key to his long-lost car. Good friends with the Spy—they both like to sneak around and mess with their enemies' heads.
 * Appearance wise, the Saboteur is tall and skinny, and wears a button-down shirt, snazzy vest and blue jeans . Slightly sunburned complexion, sports a goatee and grey eyes.
 * Possible taunts:
 * (To Pyros): Oh, Pauve ti bete! Did your fire go out, me cher? ("pauve ti bete" is "poor little thing" in Cajun French).
 * (To Heavies): Sorry, mistah! Mistook you for a cochon grand! ("cochon grand" means "fat pig".)
 * (To Scouts): Don't worry, Yankee! There's baseball in hell! along with No need for all the runnin', city boy! You just calm yourself down!
 * (To Engineers): Your machines won't be good in tha swamp, cowboy! Ever heard a' wataproofin'?
 * (To Soldiers): You're supposed to shoot dem rockets at me, not youself, ya couillon! ("Couillon" means "crazy" or "stupid".)
 * (To Demomen): I made gumbo outta da Loch Ness Monster, you really think you scare me? along with I ain't no racist or nuthin'....but YOU JUST GOT LYNCHED!!!
 * (To Spies): This ain't hide-and-seek, mistah, you might wanna get with the program! or You ain't comin' to gumbo night, Frenchie....not as a guest anyway!
 * (To Snipers): You shoulda stayed home, with y'all kangaroo girlfriend! or That's how Cajuns deal with campers, ya head-shottin lazybones!
 * (To Medics): Mah prognosis is... YOU DIED! or Take your "cures" and shove 'em where da sun don't shine, ya damn snake-oil peddla!

The (New) Civilian; The Courier

 * Uses Improvised Weapons, hopefully including at the start of each round one weapon and one accessory (or one weapon/accessory pair for balance purposes) randomly pulled from a moderate pool of weapons that aren't already had by other classes (the Medic's saws do not count against chainsaws). Slower than the Scout, but his speed may vary depending on what weapon/accessory is equipped (roller skates/blades would be hilarious but impractical). Two new modes will be added along with the class: 1) "Fox and Hounds"/"Foxes And Hounds". The civilians are the foxes. 2) "VIP Escort". A modified version of the Civilian (Purple? Grey clothing? Green clothing?) rife with Artificial Stupidity will need to be protected until he gets the handcuffed briefcase to the finish point. The civilian will not have one accent or implied nationality, but will be dressed in business or Young Adult casual and will have perfectly accented taunts that vary based on which class or subject they're mocking.

The Alien

 * A member of the species that is the source of all those WETA Workshop items for Soldier/Engineer/Pyro. Probably uses a mix of those items, along with a few of his own.
 * All Jossed. "The tenth class" has existed, but, depending on your sense of humor and personal preference, he's lying dead and buried beneath the headstone bearing his name at Mann Manor,
 * You DO realize that "Tenth Class" headstone was at a FAN site, right?

British and stuffy.

 * He will have a monocle and be English, and as such will be the Demoman's arch nemesis.
 * Sorry to burst your bubble, but the Demoman already has an arch nemesis: THE LOCH NESS MONSTER! Anyway, who will be this stuffy British class, do you think? Which role will he play?

The Mixer.
Similar to the poison master above but a little more diverse and overly dramatic. Besides poisons of all forms both fast and slow acting (he especially likes the hallucinagenic ones), he also uses team colored smoke grenades for entrances, get-aways, and disorienting the enemy. He has a gas mask but, unlike Pyro, you can see his face through it. It's basically a plastic facemask with the breathing apparatus on the bottom. His main weapon is a gas gun that fires large clouds of poisonous gas. gas tanks can be changed out for different effects. His secondary weapon is a Tommy machine gun with medium damage but deadly if the target stands still too long. Melee is a large array of syringes around his waist that are used like Spy's knife which are the only way to poison enemy Pyros and Mixers since obviously, the gas gun wouldn't work on them.He's about the same age as Scout, a Nightmare Fetishist, and a little loopy from breathing in his own gas so he slasher smiles and cheshire cat grins a lot. Not to mention mad cackling. He has low health and his speed is nothing special. He is also a big music fan so he can be heard singing random songs under his breath.

Taunts:
 * Soilder: CHOKE ON THAT SARGE!
 * Scout: YOU CAN'T OUTRUN ME. I'M THE VERY AIR!
 * Spy: OH COME ON. YOU'RE FRENCH. YOU'VE SMELLED WORSE!
 * Demoman: HUZZAH! I SLAYED THE CYCLOPS!
 * Pyro: BARBEQUE'S READY. GET THE BRATS!
 * Engineer: WELL THERE'S YOU'RE PROBLEM. YOU NEED A NEW MUFFLER!
 * Heavy: WOW! YOU TOOK LONGER THAN MOST!
 * Medic: YOUR PROGNOSIS IS BLEAK!
 * Sniper: DEAD EYE. LITERALLY!
 * enemy Mixer: GET OUT YOU IMPOSTER!


 * Well, let's see here... If Valve likes both the Poison Master and the Mixer's characters, I have a suggestion: Only one Mixer for each team, while the others can be the Poison Master.

Merasmus.
Low health, low speed, could probably make your head explode if you tempted him. Simple.
 * Okay, but what would his weapons be, what purpose would he serve on the team, and are there any other stats we need to know about? Remember, if he's a playable class, you need to make sure he'll need the help of other classes in battle.

SAXTOOOOOOOOOOOOOOOOON HALE!

 * ...What? SOMEone had to do it.
 * There's a "VS Saxton Hale" mode where everyone on a team fights Saxton Hale. That's close enough.

The Agent
Redmond or Blutarch bailed a former mafia hitman from prison in Scouts hometown. He wears team colored a zoot suit, usually a fedora, and sneakers for mobility (Spy thinks it's tacky). His primary weapon is dual wielded tommy guns with a flower motif: one Rose, the other Lilly. Primary fires Rose which uses rounds that break into small pieces and cause bleed damage, secondary fires Lilly which has a longer range and fires armor piercing rounds. Secondary weapon is an SMG with a dandelion paintjob. Melee is an umbrella with a picture of a daisy on it. Secondary fire has him open it and it's able to deflect all projectiles except bullets.

The striker
A fighter who's forte is melee, rather than the scout who is close range. He would use greaves to attack, and will be able to use the gunboats and mantreads as a weapon. The speed would be average, mainly due to running with metal on his feet, but he would be able to combo and dodge around. His speicalty would be dispatching groups, and using combos would work better if against groups. Primary would be movement options, such as improved jumping or dashing at attack, secondary would be defense, so choosing fire resistance over boolet resistance, and his melee would be footware. In terms of personality he would be down to earth, but also rather snarky and relaxed. Domonation Lines: (to scout) yeah, you run around and almost bash your head in, I'm surprised it took me to kill ya. (to demo) One eye and explosives. You are the brightest firecracker in the box, aren't ya. (to solider) Yeah, yell all you want now I just hear a CAVED IN SKULL! (to engineer) click whirr, click whirr, click whirr, bang splat. Do you dream in beeps man? (to medic) No offense, bud, but your hose can't heal ya anymore. (to heavy) Just makes you an easier target, and the fat didn't help you much either. (to sniper) Perhaps you should stop pissing yourself and pretend there is a fight going on. (to pyro) flame melts many things, but on you it just means you're a target. (to spy) You must be an ugly bastard, why else would you wear a mask all day?

Engineer

 * Courtesy of Ace Combat Zero, and some troper further down the page: Stage Four tacks on the MPBM, Stage Five the TLS, and Stage Six gives the ECM pod so that only melee attacks or an accurate frontal shot at the newly-added air intake will bring the Sentry down... Oh Crap.
 * The shotgun shown in the video for the Mac update.
 * Confirmed!
 * A suit of Powered Armor. What? The Engi Update Teaser certainly reminds some of the Forging Scenes with Tony Stark and Iron Man. Go it, it's not that unique/odd an idea.
 * The revivification machine originally built for Redmond and Blutarch. With his grandfather's blueprints, he will make his team MONSTERS!!! And this will prolly bolster a friendship between Medic and Engi.
 * That already exists; it's respawn.
 * Imagine it in Arena, though.
 * Movable spawn point for Engineer. How often have you wished you could spawn right next to your toys?
 * Teleporters.
 * The Jag will be buffed to the point where it does something. I'm thinking metal cost reduction, here - enough that the user can build a Sentry and a Dispenser without having to wait.
 * As an Engineer main, I can confirm that the Jag's increased building speed makes it the most useful melee weapon for a defensive engineer, especially when the round's just started and you need to get a sentry up fast for some basic defense.
 * A Grappling Hook Pistol. He already has the GET OVER HERE! soundclip.
 * Vehicles. Just... Vehicles.
 * A Shout-Out to Portal kit, including voiced turrets, blue-and-orange teleporters and combustible lemon launcher.
 * What if you are on red team?
 * If you're on RED team, the teleporters will have an orange glow with a small blue spinning light. BLUE team, blue glow, small orange spinning light.
 * The RED team would have red and yellow teleporters, while the BLU team would have blue and purple teleporters, Like in Portal 2's CO-OP levels.
 * A wrench that prevents him from building his own sentries, but lets him steal enemy sentries by picking them up as if they were his own.
 * Doctor Who weapons kit including:
 * a Dalek sentry that moves on flat surfaces, has a gun and melee Plunger arm
 * A dispenser shaped like a TARDIS Console.
 * A Sonic Screwdriver
 * Thrown in is a thumbs-up taunt for the Pyro. Also a bunch of voice clips, such as "I would like a hat like that." "It's a Sentry. Love a Sentry." and "Come along, Pyro!"
 * A judge's gavel, named the Court Martial.
 * The wrench replaced with a can of team-colored paint. Just splash some team-colored paint on an enemy sentry or dispenser and it's your team's! At least until the paint washes off.
 * Wouldn't the sentry try to kill you on sight though? (Unless it's a throwing item of some sort or you're directly above it...)
 * A portable dispensor placed on his back.

Heavy

 * A new set of gloves that enables either Fastball Special (if used on allies) or Grievous Harm with a Body (if used on enemies). The Heavy can easily lift and toss any of his teammates (or enemy classes, except a fellow Heavy, obviously), and the lighter classes like the Scout or the Pyro would make excellent projectiles when trying to capture or defend a point, and enemy ragdolls would make for excellent crowd-clearers.
 * A Blog Gun.
 * A gun that does increased damage while you're being healed by a Dispenser or Medic, but less damage otherwise. Could be called the "Soviet Union" or something.
 * A tricycle.

Pyro

 * A chainsaw. Given that two of his three current melee weapons are axes, a chainsaw is a logical progression. Also, he just happens to be a masked psychopathic manchild.
 * A sword that is on fire.
 * Confirmed! Sort of. It's a Flaming Axe. And it sets people on fire when you hit them with it.
 * A flamethrower that buffs Pyro's speed and jump height, either in bursts as a secondary fire or passively. This would allow him to be far more proficient at ambushing. It will likely be called The After Burner.
 * Semi-confirmed, equipping the Degreaser flamethrower along with the Powerjack and the Attendant hat does make Pyro move somewhat faster, and jump higher.
 * On the flipside of this, they actually give Pyro a ridable rocket. Useless for ranged combat, but it would allow him to close into melee nigh instantly, and the rocket could explode or stun an opponent upon hitting them as well as damage pyro a little. It would truly lead to the birth of Flyro.
 * Semi-confirmed again, in the Beta at least. The Pyro's flaregun gets an upgrade that lets you detonate flares, allowing for a sort of rocket-jumping.
 * The Flyro has been shot down, as the self-knockback of the detonator is pitifully small. It's only really useful for climbing on top of the resupply lockers.
 * Actually, with the recent buff, it's been resurrected. The Detonator jump now goes to about Scout double-jump range (I believe, from what I've seen of STAR using it)
 * Something which allows him to cover his enemies (or the floor) with gas and/or flammable oil, then light them on fire for MASSIVE DAMMAGE. Jarate/water will cause the fire to spread, like a real oil fire. The catch will be no compression blast (The oilshot will replace it), damage without first oiling is pitiful, and possibly some other problems. It will, of course, be called the Oil Spiller.
 * The mod Advanced Weaponizer includes a similiar weapon.
 * Alternatively, have the oil be a secondary weapon, being able to be set off by whatever flamethrower, or the flaming axe weapon mentioned above, which would be useful in Degroot Keep.
 * To combine several of these, the Bonkers BBQ weapon set! Primary weapon: “the Slow Burn”; a flamethrower with flame that that does 50% less damage but carries twice/three times the fuel. Secondary weapon: “the Propane Pyro/ the No-clip NOX”, a gas canister strapped to your back that he can use as a jetpack by setting it on fire. The jet pack should let him fly for up to six seconds and be activated by hitting "Jump" when already mid-air, rather than as a weapon (so you can still use a flame-thrower mid-air) and should A, drain his primary weapon fuel as it is used B, Explode and gib him if it gets hit by any weapon that can head-shot (In effect increases his head-shot hit-box)/ Melee weapon: “The Happy Fun Time Solid Fuel Preparation Device!” …a chainsaw. Secondary fire to rev-up to speed, no guarantee it will successfully rev first time, -90% damage done when not revved up +150% damage when revved up, drains primary weapon ammo as fast as a flame-thrower for every second it revs. Top that of with a chef’s hat (trim in the team colour) and a "Kill the cook" apron (or an apron with a woman's silhouette on it because for all we know, the pyro is a girl) and you've got yourself a nice little update.
 * Not exactly a weapon set, but since it's the same person suggesting all three, I'll list them together. EDIT: Looking back, if these were a set, they could probably be called "The Increasing Improbability Set."
 * First, a flamethrower that is unable to deal crits and uses 30 ammo for the airblast. The upside is it provides a larger radius for reflecting projectiles. The main attraction, however, is that it gives the user the ability to charge up the airblast to rocket jump, for a cost of 50 ammo. Visually, I'd imagine an upside-down leaf blower with a team-colored engine housing with an attached propane tank, still retaining the classic gas pump handle used by all his other primary weapons, with the head of the flamethrower formed by a small airplane engine and a team-colored propeller on the front. Naturally, it'd be called the Pilot Light.
 * Second, a middle ground between the Shotgun and the Flare Gun/Detonator. The weapon fires much like the shotgun, namely a few scattered bullets. One clip of the weapon holds 8 shots. The multiple small projectiles (relatively similar to the Medic's syringe gun) cause brief afterburn damage in addition to the initial damage dealt by the weapon, which is roughly equivalent to the flare gun's damage when used on an ignited enemy. Appearance-wise, it's a double-barreled sawed-off shotgun, similar to the Force-A-Nature. However, rather than shotgun barrels, it has a pair of team-colored slightly elongated flare gun barrels. Protruding from each barrel is a team-colored emergency flare (the weapon's ammo, replaced via pushing them out with a fresh pair in the reload animation). The weapon's name? The Roman Candle.
 * And finally, a melee weapon called the Wake-Up Call, based on old-fashioned bed warmers (metal pans with long handles, generally filled with burning coal to warm the metal) Think of it as an answer to the Scout's Sandman. If used on an ignited enemy, it has a 1-in-4 chance of stunning the enemy. Upon using the alt-fire, the user flings searing hot coals in a medium-sized range, which causes about 5 seconds of afterburn damage. The recharge for this ability would take around twice as long as the Heavy's Sandvich.
 * A Molotov Cocktail.
 * Because Pyro needs more mobility, all flamethrowers will get some self-pushback, a la Fortress Forever. This will make the detonator a lot more useful. (C'mon, valve, read this...)
 * A water/squirt gun.
 * Filled with kerosene, perhaps?
 * An Australium Ax. (See the Foundry.)
 * The ability to toast a friendly Heavy's sandvich to make it give extra health.
 * A clearly torn-from-the-street-and-stolen rusty fire hydrant(in team colours) to use as a melee weapon.
 * Something akin to Greek Fire with the ability to light water surfaces.
 * A crossbow with flaming arrows.
 * If you ignite a Sniper's Huntsman, then you get flaming arrows, so it's semi-confirmed.
 * Masks (or, in this game, hats) made of people, which s/he wears over the gas mask.

Scout

 * A set with a Hollywood/movie theme (Scout's got the athletics to be a stuntman, at least)
 * Primary Weapon: "The Show Stopper", a scattergun made of film gear (the barrels are oversized camera lenses, the stock is half of a small film spool, the handle is an elongated microphone, and the lever is a miniaturized arm of a clapper board) Deals more damage and spreads bullets on a wide arc, but fires slowly.
 * Secondary Weapon: "Caterer's Revenge" (Thermos filled with unidentifiable concoction.) Can be thrown at enemies for a brief damage-over-time effect; possibly crits or mini-crits from fire during this.
 * Melee Weapon: "The Boom" (Short boom with microphone attached.) Makes a feedback noise on impact; swings very quickly but does less damage than a bat. Could also have a taunt-kill where Scout yells into the microphone and destroys the eardrums of anyone close enough.
 * Hat is a beret labeled "Director", possibly belonged to Director from "Meet the Director" comic.
 * A lead pipe.

Sniper

 * A shopping trolley—It certainly looks like it belongs in TF2. Balancing could be tricky, though.
 * A golf trophy.
 * A sniper rifle that doesn't need to be reloaded after each shot. Of course, it does less damage than the stock one.
 * A boomerang as a secondary weapon; Alt-fire will throw it, and it will return afterwards!
 * A scopeless rifle (musket?) with increased damage.
 * A secondary blowgun that poisons targets.
 * The Primal Hunter weapon set: "The Dangerous Didgeridoo": Level ten blow-pipe. +50% time to charge up to full power. -25% ammo. Regenerate 25% of your starting health and ammo on a successful head-shot. No scope. Secondary weapon "The Bushman’s Bivouac": level ten Camouflaged Hunters Hide: a cloak made from highly conspicuous dried grass that somehow due to the power of Australia, makes you vanish from view when stationary and crouching. Does not allow you to fire any ranged weapon when crouching and un-cloaks you if you try to use melee. +20% fire vulnerability. Melee weapon: the Bludge'rs Boomerang: as a standard Kurri, except it A, looks like a boomerang and B, the taunt makes you throw it, let it orbit you, and then catch it again. This will taunt-kill anyone in contact with the Sniper (I very nearly went for a cricket bat called “The Ashes to ashes” whose description is just “Bodyline this ya leg-theory bowling ponce!”) Hat: the Stale Stereotype (Description: “What are all these corks meant to do again anyway?”)
 * Alternately, the hat will have bullets hanging from it instead of corks.
 * A fishing rod. He can use it to hook an enemy's weapon and mess with their aim.

Soldier

 * An Alamo-themed set. It would include a colonial-style musket that would deal more damage at the cost of a longer reload time. The new melee weapon would be Bowie knife, which would swing much faster than the stock shovel, but deal less damage. And it would also include, of course, a coonskin cap. Could be called "Cream of the Crocket", or something to that effect.
 * Most appropriate, considering that the term "crocket" is TF2 lingo for a critical-hit rocket. Throw in a primary weapon with some special capacity to inflict crits, and this set looks good to go!
 * The only appropriate primary I could think of for the set is a slightly downsized Davy Crockett missile with a handle. Would deal less damage and reload slower with the benefit of getting criticals more frequently. Could be called "Maybe Crocket".

Medic

 * A mini-fridge equip that replaces the primary weapon and appears as a modified version of the Medic's backpack. As in "Meet the Medic", this item will allow him to snatch up a body part of a gibbed enemy and store it away, extending the respawn timer for the affected opponent and keeping them out of the fray. Also encourages players holding one to partner with offense classes other than Heavies, who have no explosive weapons. Movement speed is decreased while holding an enemy "captive".
 * A medigun that can be used to uber sentries, but you can't uber players with it.

Spy

 * A skill or equip that allows imitating the Announcer's voice, with a set of clips relevant to the mode of play. Balance will be kept by using two rings of distance, where the Spy's imitation will sound exactly like the announcer within a short range, will be quieter or slightly distorted in a secondary range, and will not be audible outside of the secondary range. Replaces or is available as an upgrade to the Disguise Kit, and can be used with the Invisi-Watch for maximum effect.
 * A Flamethrower Lighter and/or an Underwater Hypnopen.
 * A device that, should the Spy die with it equipped, will allow him to return in the enemy's respawn rather than his own.
 * A weapon, I was thinking ballistic knife, that allows the Spy to do minimal damage (or normal damage with rather long reload) without removing his disguise.
 * Along similar lines, a fake gun that does no damage but makes his disguise appear to be attacking.
 * Along the lines on that one, the undisguised model would be one of those Bang! flag guns, making it useless for combat at the price of a wonderful trick. It could also be able to do fake healing when disguised as a Medic, like when you are being fake healed your HUD shows you gettting healed or overhealed, but the moment you stop getting healed, it shows as if you back at your previous health, as if you weren't being healed at all, which is what was happening all along.
 * Or the HUD will still show your 'overhealedness', until you're attacked.
 * A decoy grenade that produces loud, fake gunfire and randomly-sampled chatter to draw attention away from the Spy.
 * The Soho Slasher weapon set: Turns the spy into Jack the Ripper (because lets face it, an invisible guy that likes his knives a little too much is great slasher-film material) Primary weapon: "the De-activated Duellist": "Although this fine pistol was rendered un-useable for live fire in 1805, it still looks the part..." basically the flag-gun mentioned above. Let’s you look as if you are firing a weapon when in disguise, but does no damage. Taunt-kill should make the spy raise the gun to the classic duellists pose, turn on his heal and fire the flag into the face of whoever is behind him. Spy watch: "Einstein’s Egg-timer" level twenty time-manipulation device. An Hourglass that when turned over, records your position and level of health at that moment in time, and returns you to it if you take damage in the next ten seconds that would otherwise have killed you. Does not make you invisible, long re-charge time. Basically allows you to do the Jason-style slasher-film thing of not being quite dead when you should be. If you go over the ten-second time limit your next back-stab will kill yourself, as you stab your disguised past-self in the back. Knife: "the Cultivated Cut-throat": Level ten straight-razor. On a hit inflicts a bleed that will not stop (even when healed) until the spy who inflicted it is dead. 20% chance of a back-stab attempt failing. Basically, You become Sweeny Todd. You slash throats ,which is more likely that a back-stab to fail, but you can run in Friday the thirteenth style and slash people up and rely on the Dead Ringer or the Egg-timer to make good your escape and leave them to die from the bleeding as they desperately try to hunt you down before it's too late. Has no reason for existing as an item, other than pure sadism. Hat "the Understated Underhand Undertakers." a solemn black Victorian top hat with an undertakers sash in the team colour tied around it, with a matching black opera-cloak with a silk lining in the team colour. Perfect for haunting the foggy allies of 1880's Whitechapel and getting together with the Scout's great great Grandmother!
 * The Silencer: A revolver which (in addition to being quieter than most of the Spy's guns) disables the victim's voice chat and character voice for a few seconds (longer on crits, killshots, and headshots, of course). The idea being that if your victim can't talk, they can't alert their teammates to your presence, or (if combined with Your Eternal Reward) warn them that you just replaced them.
 * The False Flag: A team-colored touch football flag that replaces the butterfly knife. On a successful backstab, instead of killing the target, it switches their team colors to the opposite of whatever you're disguised as (so if you're a red disguised as a blue and tag a blue opponent, they'll turn red), and enables friendly fire on them if it was off before, allowing them to be murdered by their own teammates, for which you will get the credit. May or may not compromise your own disguise, depending on how game-breaking it is to reverse-spy someone.
 * If it removed the disguise it would have no advantage over the knife. Perhaps it could be used without breaking disguise, but when killed the enemy's corpse will return to normal to tip off their teammates.
 * New Achievement: I Really Was On Your Side: Get an enemy Spy killed with the False Flag.
 * The Hacker Kit
 * A revolver which, if the Spy dies within a few seconds of shooting a target, the target's screen or controls are slightly screwed up until respawn.
 * A cloak which makes extremely close teammates invisible as well.
 * A knife which marks the victim for death when they respawn. A pointer above their heads is visible by all teammates, through walls, and anyone who kills them gets double points. If no one kills them within 30 seconds of playing time, they're free to live, or if the spy backstabs someone else.
 * A Hacking Kit, which replaces the Electro-Sapper. It is used to take control of enemy engineer buildings. Gun down the enemy team with their own sentry, make the dispenser suck health out of them, or reverse the teleporters. It doesn't let the engineer know you've placed it, but they can still knock it off with a few hits of the wrench.
 * A cool new hat/suit, one that shows whether you're using a Mac or PC via an emblem in the center. Obviously doesn't serve much of a purpose.
 * A zoot suit

Non-Class Upgrades

 * Female character models. (Yeah, right. But this is WMG.)
 * Arguably confirmed in a Pyro-specific way, what with the UI listing Pyro variously as him and her.
 * Or you can mod them in yourself!

Team Fortress 3 will have at least 3 teams and at least 10 classes.
We've talked about the possibilities of additional teams, but a new 3+ team mode would likely be too radical a change for a simple update to TF2, which by now is 4 years old. A sequel to TF2 would not have this restriction. There have also been numerous complaints about the demoman becoming a melee-centric class. The Demoman and the Knight will be seperate classes in TF3.

There will be an achievement called You Can Leave Your Hat On
It will be for one of the fan popular couples, and thus cause shippers heads to explode.

There will be a taunt where you gain the ability to do other classes' taunts.

 * Because Pyro drawing herself up to full height and flicking away a spent match, or Spy playing air guitar with his cigarette case would be hilarious.

BLU team subsidiaries

 * Aperture Science
 * Apple Computers
 * Sears
 * Wal-Mart
 * Pepsi
 * Lowe's
 * Culver's
 * The Bilderberg Group
 * Burger King
 * Allstate
 * Best Buy

RED team subsidiaries

 * Black Mesa
 * Dell Computers (Dell’s grandfather is Radigan Conagher)
 * JCPenneys
 * Target
 * Coca-Cola
 * Home Depot
 * Five Guys
 * The Trilateral Commission
 * McDonalds
 * State Farm
 * Circuit City

Mann Manor was Blutarch's attempt to cut out the middle-man and assassinate his brother and if TF2 had a plot, this would have been the climax.
It's clear from the view in RED's base that this is Redmond's manor, and that he's in a similar state to Blutarch. It took over 100 years, but Blutarch finally caught on to how Redmond also has an immortality machine. He realized that waiting was pointless and that going for the land itself resulted in stalemates. So why go for the actual land when you can just kill the guy who owns it and buy the land for a low price (Considering that it's pretty shitty land with no real resources)? He sends in BLU to overtake the Manor and kill Redmond right then and there.

BUT Redmond anticipated that Blutarch would realize he too has an immortality machine. So RED is on guard at the manor, ready to shoot down anything wearing blue. The Horsemann, being Silas Mann's Spirit, can be explained as Silas not wanting to take his nephews' bullshit anymore and deciding to break both of their toys (Kill their mercenaries). RED and BLU make a silent "Try to kill him, but we'll still shoot you" truce because the Horsemann is purple. A wild card to the both of them.

Both teams work by using a Clone-O-Matic with the same nine mercenaries.
The reason so many of them are killed, but can strangely remember everything they did a few seconds prior to being blow up by a crit rocket, is because both RED and BLU have their own set of machines that clone the mercenaries with their data. Every time they die, the Clone-O-Matic takes some time to recall the data of the person lost, to then clone him again so he can do better. Because, given the mental state of the nine demented mercenaries, they don't have an exactly sane survival instinct... BLU.'' Unbeknownst to RED, Administrator has DNA samples of the entire RED team on file, and is testing beta clone versions of them-- Team BLU -- against RED. The BLUs are currently full of bugs, but Admin's ultimate goal is not merely to create weapons-- it's to perfect these prototypes, creating a team of genetic supersoldier templates available to TF Industries' highest bidder... rendering RED expendable. Her partner in crime is, of course, the only original member of BLU: Dell Conagher, world's greatest genetic engineer... and double-agent for the RED Team.
 * This, in turn, explains why both RED and BLU teams look exactly the same. The Administrator may have chosen them, and both Redmond and Blutarch wanted these men for their respective operations. So instead of hiring more mercenaries, they just clone them every time they go to fight.
 * This also explains why would there be more than one character of a class in one game: Sometimes the machine mucks up, and ends up creating endless waves of Scouts, hordes of Demonic Spies, or a brickwall of Heavy Weapon Guys.
 * In addition it also explains why in the Meet the Team videos the characters kick so much ass. You can't create clones without an original strip of DNA - those ones we see in the Meet the Team videos are the originals, and as such possess many times the ass kicking power.
 * Additionally, the DNA was supplied to both RED and BLU by a third company, Genetic Resources National (GRN). This explains how both teams have the DNA.
 * ''Alternately, only one team has cloning capability:
 * Alternately : All the characters of the same class are twins/triplets/quads, etc.
 * This would also explain Pyro's changing gender on the class picking screen- unlike with the other mercenaries, the cloning machine doesn't bother to specify the amount of X chromosomes each time because it doesn't matter.

The real BLU team is actually completely different from the RED team.
...and what we're seeing of the "enemy" in the "Meet the Team" videos and the game itself is actually a simulation that RED is using to train its up and coming team. Granted, through the unfortunate like-mindedness of Redmond and Blutarch - or, more probably, the Announcer's, being CEO of both companies, own meddling - BLU is probably doing the same thing with their own set of nine. Seeing as RED is portrayed as the ever so slightly more "heroic", it makes sense that they're the ones being exhibited. To clarify:
 * The RED team, with all their personality, are actual humans, and, more importantly, the originals. The BLU team that is shown is a virtual copy of RED so that they can practice with at least somebody that is their equal - thus explaining why only a simple colour swap differentiates the two.
 * This pretty much explains why none of the originals have actually died...yet. There's no real threat to the RED team, as of how much the audience knows thus far.

Meet The Team is canon. Team Fortress 2 itself is the Game of the Movie.
It isn't Cutscene Power to the Max that's being exhibited in the promotional videos. The videos are the actual story, as of yet not fully realized, and Team Fortress 2 is an adaptation. Adaptation Decay was necessary to keep the game fun and balanced. Really now, the sheer skill of these guys indicates that if you went up against that team, you'd be utterly screwed. Everyone else is merely imitating them in order to try and match them, thus why you can choose your own classes. They are a bunch of fellows with nothing to lose, banding together for a common cause... A cause which nobody has a bloody clue about. Thus the application of The Worf Effect to the Heavy in the non-Heavy-focused videos is justified, since only the featured class is "played" by the real one while the ones getting slaughtered are these impostors. The "real" Heavy can tank all those shots and doesn't afraid of the Scout, etc. Alternately: The Meet the Team videos feature the originals; all the player-controlled characters are clones. They're given the signature equipment and skills of the originals, but they lack the experience and general competence of the originals. Mostly.
 * Or the BLU Heavy could just be the RED Heavy acting as one, if the theory about the videos being RED's corporate propoganda is to be believed.
 * The BLU spy seems to be aware of this: "if you managed to kill them I assure you they were not like me - and nothing, NOTHING like the man loose inside this building." Similarly, the RED Demo states that "If I were a BAD Demoman, I wouldn't be sitting here, discussin' it with ya, now would I?"
 * Confirmed.Meet The Team is canon, as well as the comics, and it's not propaganda, although that is Miss Pauling's cover story, at first. The Administrator is spying on RED in case they decide to get uppity... and by the looks of things, they are starting to get there. The videos were directed by a pompous little fellow with grand ideas, who had a convienient "accident" courtesy of Miss Pauling. The Administrator, meanwhile, is looking for new directors...
 * Related Theory The canon teams are on the startup screens. There are officially only 9 mercenaries hired. This splits the 9 between 2 teams. Red is Pyro, Medic, Heavy and Demo. Blue is Engineer, Soldier, Scout and Sniper. Spy is… complex…
 * Related Theory: The BLU Team is Screwed. In Meet the Spy, the BLU Spy is killed by friendly fire, and it's implied that the BLU Scout was killed offscreen. Based on their dialogue, it's possible that they were very nearly, if not equally, as skilled as their RED counterparts who star in the Meet the Team videos. I know that doesn't explain the BLU Scout, since, but think about it: would he really jump into that sort of situation with no prior knowledge of his persona? Odds are, the BLU Scout really was competent enough to kill "dime-a-dozen backstabbing scumbags" with ease, lending credibility to his skills. And without him or the BLU Spy in play, that makes the odds 7:9 in RED's favor at best. That's assuming the Medic and Pyro have representatives equally as awesome as those classes that have already been introduced.
 * Related Theory: All of the BLU Team members seen on the startup screen (and outside of the videos) will eventually defect to RED. We can see hints of this in Engie’s Comic and Meet the Team video. Dell is perfectly willing to go behind his employer’s back For Science! and More Gun… and did you ever wonder why a RED Engineer was sitting in front of a BLU pickup and drinking the other team’s beer? Here’s a hint: Dell didn’t die. He just changed shirts. By extension, Scout, Sniper, and Soldier’s “Meet the” videos take place after the Spy uses his Dead Ringer to help fake Scout’s, Sniper’s, Jane’s, and Tavish’s (from the WAR update) death. The Administrator won’t notice because all mercenaries look alike to her, Miss Pauling won’t dare to protest… and the boys will eventually figure out that they’re being played for saps… and when that happens… God help TF Industries.
 * Related Theory: The Team will eventually become immortal. Let's face it, as it stands now, our heroes have little love for their bosses, nor do they have any reason to have any. For either of the Mann brothers to win the land-grab, some of the team will have to die. And it's recently been revealed to the members of [RED] that Admin will go after the people and things they love if they don't fall in line; she, of course, couldn't give a crap about their safety or that of their loved ones. That's quite a lot of trouble for their paychecks... but there is a way the team's little problem could be solved. They could enlist the help of Dell, Medic, and their new improved life-extender machine, guaranteed to make it's users not only immortal, but eternally youthful, and absolutely, positively inde-friggin'-structable. Or, if the hint in "Meet The Medic" about BLUs reserves is viable, the two men could secretly perfect Soul Transference. Having done so, the team could not only financially destroy the Manns, but the Admin as well, draining their bosses bank accounts as they demand increasingly higher salaries for their excellent, fantastically fun jobs... ensuring that they never stop playing the best game ever.
 * Related Theory: Monday Night Combat is actually Team Fortress 2's world in the future. TFIndustries products have been prominently featured, and one has to wonder why... In Team Fortress 2, two corporations, RED and BLU, wage a secret war to control the world. In Monday Night Combat the world has become a Consumerist Dystopia where people are entertained by a deadly sport that only has two known teams, a red team known as the Hotshots and a blue team known as the Icemen. What none of the teeming masses know is that Monday Night Combat and the entire world are controlled by the perpetually rejuvenating... A. Administrator, B. Miss Pauling, or C. ... cabal of nine mysterious (yet very familiar) men, known only as the board of directors of TFIndustries.

The Control Points are actually network hubs for ARPANET
While the time frame isn't precise (TF2 takes place in 1968 and ARPANET wasn't first online until 1969), one could think that the reason you're trying to activate all these control points to "win" a control point match is so that your side can control the flow of information on this budding Internet prototype, ensuring a distinct edge over the opposing side once the 21st century rolls around.
 * This explains why, in the time setting of the game, the internet is "a thing that exists!"

In the Team Fortress 2 universe, Howard Hughes is a Jarate master.
Which is why he stockpiled bottles of his own piss. Maybe using milk bottles instead of mason jars is an American varient of the martial art. Maybe he learned of Jarate in the saw the same ad Sniper saw. Or maybe he invented it and taught it to fellow eccentric tycoon Saxton Hale.

Zepheniah Mann decided the afterlife for his sons Blutarch and Redmond.
Just as Zepheniah Mann willed a curse that he would haunt those who used firearms over his burial grounds (KOTH Harvest's Halloween version), he decided the afterlife and fate of his sons in his last will and testament. In the new comic "Loose Canon," parts of the will are repeated on Page 4 ... "Zepheniah Mann's will: To my layabout, brain defective sons, Blutarch and Redmond, I leave the greatest curse of all--partnership. What land I have purchased in this new world is to be split evenly between you both. You have wasted your lives bickering over nothing, and so I leave you dimwits something of consequence over which to feud."

Later in the comic, Blutarch says this to the BLU Engineer : "Blutarch Mann: Every day I'm dead a little longer, Mister . I have seen the other side. There is nothing there. FIX. THIS. MACHINE."

If Zepheniah Mann managed to will himself as an immortal ghost to haunt those who desecrate his grave, what if he also managed to will Blutarch and Redmond a curse that, when both of them die, they will be sent to The Nothing After Death? They "wasted their lives fighting over nothing, so the only something they have, in this life or the next, is what Zepheniah Mann has willed to them ...
 * Consider this... what if Zepheniah didn't purchase any land in America? Or his use of "new world" was a self-aware reference to a different sort of real estate?

The mysterious man in the last will and testament is the founder of SpyTech.
When the backstory started popping up (Zephaniah Mann arc, Demoman/Soldier War arc, etc.) SpyTech just stopped being mentioned. Zephaniah left him nothing material; but all information Mann had at the time, ranging from predictions on the latest trends to the state of backroom politics, etc.. Using this information, the mysterious man manages to build a company out of nothing. It can also be inferred from this theory that the SpyTech founder is aware the entire RED/BLU war is a sham, and is using the war to further his own goals. As to why he's so secret, I have two reasons: deception and manipulation. Firstly, he values secrecy on the matter above all else. Helen only has part of the photograph (and, presumably, part of the will) that doesn't mention Founder. He had it partly erased to prevent anyone finding the secret. Secondly, he is secretly manipulating the entire war to profit from the purchases accumulated by RED and BLU, which he probably owns anyway. The whole war is drawn out by TF Industries, which is being manipulated by SpyTech into prolonging the war. Put short, SpyTech is the actual force driving the events of Team Fortress 2, and the founder is using an improbably convoluted plan designed for manipulating the events of Team Fortress 2 to his own gain. Expect to see him in the story later.
 * Related: The Unseen Man Is....
 * Related to the Scout, Soldier, Heavy, Demoman, Spy, or Medic
 * Related to Miss Pauling
 * The Pyro (Or the Pyro's ancestor)
 * Radigan Conagher
 * G-Man
 * Cave Johnson’s father.
 * No one of particular interest (Valve is just trolling us)

Each of the olde!Team is a famous person from that time period.
According to the Official Wiki, it goes like this:
 * Scout - Billy the Kid
 * Soldier - Stonewall Jackson
 * Pyro - Abraham Lincoln
 * Demoman - Alfred Nobel
 * Heavy - John Henry
 * Engineer - Nikola Tesla
 * Medic - Sigmund Freud
 * Sniper - Davy Crockett
 * Spy - Fu Manchu

Prolonged exposure to Australium causes people to become Australian.
This is Radigan Congaher before using Australium. This is him afterusing Australium. The reason that the Sniper doesn't act Australian is that he isn't in constant contact with Australium.
 * That, or the Sniper is required to shave and keep his body hair hidden at all times as a clause in his contract, or otherwise his rugged handsomeness would just turn the battles into "Spooning With Sniper".
 * Spooning with Sniper, eh?
 * Related: Australium, while enhancing natural intelligence, depletes common sense. If you notice how Radigan had gotten better with his inventions, yet cut off his entire hand, this might mean that Australium, while making you more badass, muscle-bound, and smart, will make you have poorer judgement in life. This is why Australia is the most technological country on the planet, yet they decide their king with a boxing match against a kangaroo.

The Mann's Immortality Machine was the prototype for the Medi-Gun and Ubercharge.
The machine directly lengthens life, and upon 'reviving', the 'victim' ends up with color-coded glowing eyes much like the official 'Ubercharged' Avatars from Valve.

Helen The Administrator is…
The granddaughter of Zephaniah Mann and Elizabeth, through her daughter Emily and either of the Mann brothers. Elizabeth and Zephaniah’s relationship may have been based on more than mere trust. Elizabeth’s presumed daughter Emily, seen here bribing Radigan with Australium seems to have reaped the benefits of this alliance… in more ways than one. Though its canonicity is hotly debated, A rather… can be found in Redmond Mann’s current residence, Mann Manor. Winning her attentions may have been another point of contention for the boys. A disturbing question remains… why would Emily want to damn the two men to an Ironic Hell through bribing Radigan to sabotage the machines? The boys may have toyed with her affections far too much… but there’s yet another disturbing question to answer. This theory has, until now, been built on the supposition that Emily was Elizabeth’s daughter from a previous relationship. But what if Emily had blood ties to the Mann fortune? If Emily was the illegitimate daughter of Zephaniah by his maidservant, she would have had no sure guarantee to his fortune, a burning desire to see two full-blooded but unsuitable heirs punished, and an utterly insane drive to do whatever it took to utterly destroy the both of them. Judging by the looks of things, Emily infected her daughter with that thirst for vengeance as well.
 *  Alternately, Elizabeth is Helen’s Aunt, thus removing some of the incestuous connotations of the above theory.
 * Using the feud as a cashcow for TF Industries and its subsidiaries. RED and BLU may own most of the world, but TF Industries is based in 1960’s Washington, and is thusly the weapons supplier to one of the world’s biggest superpowers… in this particular Alternate History, its the uncontested biggest. Redmond and Blutarch are clearly willing to pay Helen big money to see their side win, thus furthering her ultimate goal of draining their fortune while seeing them suffer. Every weapon in the game - and I mean every weapon - is either owned or a product from TF Industries. The Spy gets his stuff from a branch of the company (scroll down), the Sniper learned Jarate from a mail order catalog from the same branch (note Saxton Hale, who is also present on the Mann Co. catalogue), and so on. Therefore, TF Industries stands to gain a lot of money from this conflict. Note, also, that it's Team Fortress Industries, and not another, more mundane weapons company. Therefore, the idea is to keep releasing new products to the poor saps, not only to find out what will work and what can eventually be incorporated into the military (not the teleporter, obviously), but to make money as frustrated Snipers pick up cleverly planted Jarate catalogs, and Engineers keep sending for replacement tools and materials. Logically, this war is therefore over absolutely nothing and TF Industries is slowly getting richer and richer.
 * Basically Confirmed, but it's even simpler than that. Taken together, RED and BLU don't own most of the world. They own ALL of it, and by extension, so does the Administrator (who just so happens to be the CEO of all three of the world's MegaCorps), for as long as she can keep the conflict going....
 * The person the third life-extender machine was built for. She's actually Elizabeth, Emily and all other females of that family line. Her life extender machine works a bit differently, because it only needs to be used once in a great while, instead of her being attached to it all the time (Since Radigan Conhager didn't quite finish it before going crazy with Australium radiation, she had to rely on the combined intellects of Nikola Tesla, Thomas Edison, Alexander Graham Bell, Michael Faraday, Guglielmo Marconi, Louis Pasteur and Marie Curie. Needless to say they made significant improvements to the design.) When she does use it, she regresses to the body of a ten-year-old girl, with all her memories and plots intact. She passes for the daughter, or granddaughter of her previous persona, and takes on a new name. She ages as people do normally, and judging by how she looks now, she won't need it again for thirty or so years.

The Brother's Feud wasn't so trivial after all
Based on the perception taken from the Engineer update comic, Blutarch appears to be the first person to think of ideas for things. Perhaps that's what their life growing up was like. Blutarch would come up with an idea, and Redmond would manage to replicate the idea perfectly (In Red), albeit some time after his brother. They would then fight over who really thought of it first. Their father could only see the boys as an identical pair, with the only differences being colors So he was of the impression they both came up with the idea at the exact same time, rather than Redmond was imitating his brother. Years later, this was blown completely out of proportion and now both brothers are waging war on each other, each one thinking they have a fair claim.

Radigan Conagher is Ferb from the future
"The Engineer: First time I heard he had one, Ma'am. Radigan Conagher is not a very chatty man."

The Heavy is…

 * The long lost brother of Soda Popinski Let's check the similarities: Bald, Russian, Healing food with Instant Metabolism, Skilled boxers, Plus they have the same uppercut style which either suggests a relation or training under the same instructor, Rivals with a small quick guy with a New York accent
 * Alternately after the war against RED and BLU was over, the Heavy returned to Russia, became a boxing instructor/trainer and Popinski became his most successful student, making into the World Circuit of the WVBA.
 * …related to or is General Nikolai Alexandrovitch Zakharov Both are bald, heavyset Russians. General Nikolai Alexandrovitch Zakharov once stood unflinching under a hail of automatic fire, earning him the nickname of the Man of Stone, while the Heavy is capable of taking large amounts of damage from multiple weapons and moves slowly.
 * Ocelot Russian – check Rotary Gun – check Can kill people by pointing fingers and saying "bang" - check … Man, he's really let himself go.
 * Jorge-052s ancestor
 * Father Grigori years later. Think about it; both Russian, both crazy, both name their guns and seem to enjoy killing, and both are bald. Assuming that TF2 and HL are the same universes, then after the combine took over, Heavy decided to do something else with his life and move away back to Ukraine, which is where the Half-Life 2 game takes place, which is in RUSSIA, and live in Ravenholm. He, of course, joined the resistance and fought against the Combine, losing some weight and growing a beard in the process. He maintained his unbalanced mental state, but switched slightly for the better. While living in Ravenholm, he became, or already was but more extreme now, a Catholic or Christian.
 * …related to Sinistar. Heavy: "I am Heavy Weapons Guy" "I live" "run, cowards" "hide, cowards"… Sinistar: "I am Sinistar" "beware, I live" "run, coward" "beware, coward" Also, while he never explicitly says it, the Heavy does hunger.
 * a sentimental man who names his guns after loved ones. He has a wife, Sascha, and a daughter, Natascha. (Note, however, that Sas(c)ha is also a male name in Eastern European countries.)
 * All of Heavy's guns are named Sascha, so the voice clip doesn't need to be changed. Sascha can be short for Natascha, she just uses her "full name" because she's bigger.
 * More affected by his past than he lets on. His dad was killed fighting the Communists in 1941, his mother and sisters were sent to a gulag, and it proceeded to burn down, all the soldiers dead. Let's say for argument's sake that Poker Night At the Inventory is canon. He was apparently hired by RED because he killed many soldiers. Heavy was the one who burned down the gulag, killed the soldiers, and because it was his first taste of trauma and death, was somewhat shaken by it. It'd explain why he won't talk about it with The Director and keeps changing the subject back to Sascha. It'd also explain his attachment to Medic. He's really afraid of death and is in denial about respawn.
 * A member of the Orlov family. Because Orlov Sandvich.

The Heavy's shotgun is named Boris.
Because that would be punny.
 * I always just figured Boris was Heavy's name.
 * It's too tiny to deserve a name.
 * Perhaps the more manly his weapons are named, the tinier they are(and vice versa), like Hagrid's pets.

The Heavy suffers from Delusion Companion Syndrome
In which victims believe inanimate objects to be sentient. The way he talks to and fawns over his gun isn't too strange; lots of gun owners take great pride in their weapons and give names to them. No, the companion here is the Sandvich. Not only does he talk to it, it seems to talk back to him ("What was that, sandvich? Kill them all? Good idea!"), or at least only he thinks so. He sings songs in its praise, warns others to "run from the sandvich", as if it were alive and malicious, and even says things like, "Sandvich and I are coming for you!". Note he put "sandvich" first, indicating that the sandvich is in control. How did he get these delusions? Brain damage via food poisoning- a sandwich full of bologna and cheese, With all the sweat and filth of battle staining it, is more than likely to harbor nasty parasites.
 * It's gotten worse. He's now convinced a bar of chocolate is his Sandvich.
 * Not anymore, since an update made quite a few lines Sandvich-specific.

The Soldier is…
A supporter of the war in Vietnam. The thought comes from the gunboats. The reason the Us entered the war, was because US ships were attacked in the gulf of Tonkin. What were they attacked by? Gunboats. The US used Gunboats to enter into the war. The soldier uses the Gunboats to get into combat faster and easier. (figured this needed saying since no one else has said it. Anywhere.) It's possible he bought his way to Vietnam (Army still won't accept him, thus he's still a civilian.) and went on a killing spree again. He likely then was hired by RED/BLU, who were impressed by the amount of killing he could achieve on his own.
 * Saxton Hale’s son. Soldier couldn't join the US army because he's actually Australian.
 * Canadian/Born on a foreign army base. He couldn't get into any branch of the U.S. military because they wouldn't believe his fake ID, which was the image from a "We Card Under 18" sign with a wallet-size photo of himself glued on. He wanted to get into the U.S. military so he could be in a real military, and kept it up into the 1960s so he could actually fight instead of guard anything with the word "peace" in. He calls the Engineer "Canadian" either because he considers Engie no different from a draft dodger or because they actually hail from the same small town in Manitoba. He doesn’t know the Army accepts Canadians. Or he could be from China, given his obsession with Sun Tzu. All he knows about American is via second hand information, especially war movies.
 * A woman/intersexed. She wasn't allowed in the army for medical reasons. That medical problem is being the wrong gender. She was always a fairly masculine child, and was extremely violent, and going to war seemed like something she would really enjoy. Nine years of heavy smoking, screaming at enemies, and inhaling gun powder have turned her voice gravelly and manish. To her, only civilians can be women, which is why she got so panicked and upset when apparently Demoman called her a civilian- she thought he'd figured it out and spilling her secret.
 *  Of German descent Soldier’s bio says he’s from the Midwest, which has a high population of German immigrants. He changed his name to avoid suspicions of treason, and because he honestly did want to fight for America.
 * Gay/Bi Self explanatory. Adds a level of sadness to the events of “WAR!’’
 * Actually called Jane Doe: At least the BLU Soldier. His parents were not only "clever" and decided to give their child a punny name but wanted a girl as well and were very disappointed when he wasn't. He doesn't have to assert his masculinity or anything by changing his name or using an alias, but he still wants people to know he's not a woman. That's why the sign on his apartment window says "Mister Jane Doe".
 * Right about a surprising amount. Sniper's name is actually Barble Bapkins Mundy, Engineer is Canadian, and the Pyro's name is in fact Joe(sephine?).
 * A Poet. Many soldiers wrote war poetry in WW 2, but Soldier, noticing a distinct lack of 'war is awesome' poetry, decided to fill that market himself. He isn't very good at it.

The Soldier's description of Sun Tzu's achievements is completely accurate.
Although it would be easy to dismiss the Soldier's monologue as the ravings of a lunatic, it's been established that famous figures from our universe's past were much more badass in the TF2 universe -- Shakespeare Shakespearicles was a superhumanly-strong writer who founded America and invented the rocket launcher, Alfred Nobel was the original Demoman, etc. -- and so it's possible that Sun Tzu actually was some sort of UFC Noah.
 * The completely part was jossed at the Meet the Director comic. Said director was calling out Mr. Doe (the Soldier) for one of his depictions. The Soldier is undoubtedly a Cloudcuckoolander after all, and not just for Sun Tzu...

The Soldier believes wearing the headgear of a fallen warrior imbues him with their power.
Explains his large number of anachronistic hats.

The Soldier was turned away from the war because the Announcer had a hand in things.
The Announcer saw his potential as a deadly mercenary and denied him entrance to the war as a test. He passed.

The Engineer is...

 * ...Radigan Conagher. In Meet The Engineer, he says that the sentry was "designed by me", but in Loose Canon, we can clearly see blueprints for the sentry in Radigan's workshop. Furthermore, we know that Radigan built a third Life Extender after building the first two (i.e. after working out the bugs in the original design), which he is presumably keeping to himself. He's pretending to be his own grandson to avoid suspicion from his employers. Also, the life extender explains how he managed to earn 11 PH Ds and work for 10 years in the oilfields.
 * Which makes you wonder whose corpse was in the grave Blutarch dug up...
 * compensating for childhood torment by playground bullies. Engie's favorite "toy" was the sandbox. He liked to build undefined sand structures, the larger the better, but the bullies were always there to destroy them. So he started building stuff that kills people. This is also why he reports every destroyed building: It brings back unhappy memories.
 * ...Dr. Horrible's father. Mad science obviously runs in the Conagher family, as illustrated in the Engineer update. Furthermore, while the events of Sing-along Blog happen in the late 2000s, TF2 takes place in the late 1960s. Billy (whose real last name is Conagher; he trained himself out of an accent so he could be taken seriously) took the plans for the freeze ray from Dell but modified the required element from australium to wonderflonium. However, he has strained relations with his dad for not only using, but improving sappers to use on vans. And moving on from this...
 * Captain Hammer grew up reading Saxton Hale comics and stuffs tiny Homewreckers in his gloves. His outlook is about the same as Saxton himself, and notice it only takes one punch to destroy the controlling device (which is made of metal) but Dr. Horrible survives the blow?

The Engineer's PhDs are in...

 * 1) Biological engineering.
 * 2) Biomedical engineering.
 * 3) Chemical engineering.
 * 4) Civil engineering.
 * 5) Computer engineering.
 * 6) Electrical engineering.
 * 7) Mechanical engineering.
 * 8) Military engineering.
 * 9) Mining engineering.
 * 10) Nuclear engineering.
 * 11) Software engineering.

The Engineer has several Minors as well as PHD's.

 * Specifically, in music and art. He knows Kicasso's work, and he sure can play that guitar!
 * Now explain why you linked to a webcomic.

The Demoman is

 * ... related to Chef from South Park. Think about it, his parents are both Scottish, and I think his mum is blind and... thats all I've got on that one.
 * ... in some way related to Doc Facilier or Mama Odie. Well, not necessarily voodoo magic, but especially with the incessant voice from the Eyelander, he'd no doubt have friends on the other side.
 * He was born on November the fifth or Bonfire Night, aka Britain's 'excuse to light fireworks' day.
 * ...Related to, or is, one of the Stabbington Brothers. If you glance at Demoman's concept art, this is not as crazy as it first sounds.
 * ...a Scottish relation of Frozone, going off the below shared universes theory.
 * ...secretly a master spy. Because he is the least likely person possible to be one.
 * He was adopted and raised by the Demoman of Team Fortress Classic and his wife, though he never knew about this and it promptly became inconsequential upon his blowing them up.
 * ...colourblind. As well as being one eyed.
 * ...missing a leg. He has a prosthetic when not using the Bootlegger.

The Scout is...

 * Definitely not The Spy's son. Confirmed by Word of God.
 * Relatedly: Every class, except Scout, is the father of one of Scout's brothers. Poor kid has no idea.
 * ...of mixed heritage. He was born in the Bronx, but his family moved to South Boston. Hence his accent. He had to develop his skills at running and fighting in order to survive in the face of discrimination, as the Scout is a Red Sox fan.
 * ...the grandfather of Ellis . The Scout got to know Engineer's daughter and after finishing his job as a mercenary he settled down in Texas to be with her. His son moved to Georgia, where he met Ellis's mother. Besides, the family resemblance is pretty obvious.
 * Alternatively, he could be Nick's father.
 * ...the father of Ness from EarthBound. Where do you think Ness's dad got much money if he just works making hamburgers? Ness's SMAAAASH hits are clearly inherited from his father's ability to BONK enemies into submission, as are his PSI powers; the Scout's double jump is a form of levitation. Going further with this theory, note how Ness is the slowest of the four playable characters in Earthbound. What does the Scout take pride in? His Speed! The Scout himself used to be slow as a child, and is embarrassed that his son is suffering the same problems as he did.
 * ...the son or nephew of Donnie Donowitz. Bonus WMG: Combining this with Word of Tarantino results in Inglourious Basterds, Team Fortress 2, and True Romance occuring in the same universe.
 * ...the father of Harley Quinn. Scout works as a mercenary, limiting his time with his own children. Scout and Scout Baby Mama divorce, and she takes the kids to Brooklyn. One of these children is Harley. Harley longs for paternal approval, which is ultimately the seed of her submissive nature in most of her relationships, especially her romantic ones (The Joker, Poison Ivy).
 * ...the son of Yankee Irving from "Everyone's Hero" Yankee was about 7 in 1932, that's more than enough time to have a 19 year old son by 1968. Seeing that he's a Yankees fan, while the Scout is from Boston (complete with Red Sox refrences in his achevements), they must REALLY dislike each other.
 * ...the father of Byrne Faraday and grandfather of Kay Faraday. Scout is the most adept of all the classes at retrieving the intelligence (or at least he was designed to be so) and it most likely contains lots of incriminating documents (and thus could technically be perceived as "the truth"). Ergo, his last name is Faraday and he's most likely also some sort of a relative of Michael Faraday. The only things he needs now are a Yatagarasu badge and some kind of a chemical weapon.
 * ...the past self of Goddard from Time Splitters: Future Perfect. If the Scout from escaped one of the maps in 1968, the year the game takes place, he could have served in the Vietnam War, like Goddard. They both have some similarities.
 * They wear similar hats, wear dog tags and have rolled-up sleeves
 * They use similar weapons, like baseball bats, shotguns and pistols. (Also, it would make sense for him/them to learn how to use a variety of weapons later)
 * They are conceited ("You got the real deal right here, baby!" vs. Almost all of Scout's lines)
 * They look eerily similar
 * SCOUT IS BOO!

The RED Scout is a Red Sox fan from Boston; the BLU Scout is a Yankees fan from Brooklyn
No wonder they hate each other.

Scout suffers from a severe Inferiority complex
He has incredibly low self esteem as a result of him being the runt of the litter and his superior older brothers soaking up more of his mother's attention, somewhat like Ron Weasley. The only thing he could train himself to do better than them was run and play baseball, so he takes far too much pride in those abilities because of it. This is also why he is constantly proclaiming his superiority to others- he is desperately reassuring himself.

Scout's brothers will be shown at some point
And they will look suspiciously similar to the rest of the team, right down to a mechanic and a faceless one.

The Sniper is...

 * ...part-british. This may explain why his accent's more cockney than Australian. Perhaps he's related to the infamous aging superspy, Bruno Lawrie... this may also be why he hates The Spy.
 * ...a Kiwi. He pretends to be from Australia rather than from New Zealand, because if he didn't, Saxton Hale would probably murder him.
 * The Scout's father. He hates the Spy so much because his wife - the Scout's mother - left him for the Spy.
 * He's Cody's Father. Sniper is a neglectful (or divorced) dad. It idly and cleanly connects Team Fortress 2 to the Disney Animated Canon.
 * Alternately, the Sniper is vaguely related to McLeach, which is why his father severely disapproves of the Sniper's career choice.
 * Pirelli's descendant. Apparently, the "Piss-In-Jars" thing runs in the family, only Sniper found a somewhat more practical use for it.
 * The first white people to reach Australia were Englishmen, who sent convicted criminals there. Pirelli had a child, who grew up to be a criminal. The child was eventually sent to a prison colony in Australia.
 * Bushwacker Bob's son. When the Sniper says "put Mum on the phone" he wasn't taking about his mother, but his grandmother.
 * ''The child of Eustace and Muriel. They live in the middle of Nowhere and Everything Is Trying to Kill You. Eustace also seems the vindictive type who just harps on what a crazed gunman his son is.
 * They live in the middle of Nowhere, Kansas, but many Australians have Scottish Ancestry... so... Huh. Maybe Muriel has an aunt?
 * 'Saxton Hale’s brother. ' Think about it for a second. Why would Saxton, a hunter himself, who has, in the past demonstrated a cheery, callous disregard for the life of animals, children and hippies… a man who has been in a romantic relationship with the most murderous, hateful woman in existence, who --gleefully supplies her with deadly weapons for the sole, express purpose of killing human beings—disapprove so heartily of Sniper’s career? They both deal in murder. If anything, their relationship smacks of sibling rivalry, someone ribbing his little brother for not having the guts to punch a Spy rather than shoot him, but helping him out just the same. Saxton looks so much older because of all that Australium-induced testosterone. As for their parents, they disapprove of Saxton’s career, and had pinned all their hopes for their fading future on their seemingly more taciturn and compliant youngest son, hopes which were summarily dashed when he chose a similar career to his brother.
 * Relatedly: Sniper is the inventor of Jarate. Saxton’s too much of a fisticuffs kinda guy to have come up with this idea, but Sniper demonstrated it… on him… Saxton Hale : The events of this comic actually happened… to me! then sold him the rights in exchange for a 75% cut of the profits and an endorsement deal.
 * Alternately, The Sniper is Saxton Hale. When “Saxton” says that the events of the Jarate comic actually happened to him, he’s telling the unvarnished truth. Sniper is, indeed, a descendant of Barnabas Hale and the CEO of MannCo, but he neither wanted the drudgery nor the direct responsibility of running such a company, when self-employment seemed far more adventurous and lucrative. Sniper, by nature reclusive, created the Saxton Hale persona ( perhaps even writing the comics himself ), as a company figurehead and a sly commentary on his home country. Mister Reddy and Mister Bidwell are not his butlers, but rather, the acting CEOs of MannCo, though they defer any particularly pressing business to Sniper. Though the events of the comics in which Saxton Hale appears are largely fictional in-universe, the call from Miss Pauling was at least partially real, save that Miss Pauling and Helen are likely unaware that “Saxton” is actually Sniper… of course, given that a child bearing a striking resemblance to Miss Pauling appears on the cover of Girl’s Adventure, Pauling may be Sniper’s trusted Mole, his daughter, or both. This also means that the rumors “Saxton” spreads about Helen’s relationship with him are born out of either a raging crush on her, a desire to piss off his boss, a tiny grain of truth… or all three at once.
 * A dhampir. Just look at his teeth and his vampire hunting item set.
 * A person with a passion for knitting. In one of the christmas cards, he gives BLU Scout a handknitted jumper, and one of his game items is a sweater vest. Perhaps he knits in his spare time.
 * Someone with more than a few issues. His domination lines would indicate severe rage problems.
 * ...Wesley. We only know his last name (Mundy), so this should be his first name. Why? Because Wesley snipes.

The Sandvich is...

 * ...PEOPLE! That mysterious meat slice? IT'S NOT "JUST HAM".
 * It Gets Worse. The Heavy still talks to it. Perhaps that Sandvich WAS a loose cannon but a good cop. Hell, the proof has been on Youtube for quite some time.
 * Even more so when you consider that the description on Pyro's toque blanche(You're today's theme ingredient!) implies him to be a cannibal. Well, if one of the team does it...
 * Made by the Medic for the Heavy. The "V" in "Sandvich" could be used to represent the accent of either character, and it's a healing item. This is a little bit more likely if the above WMG is true.
 * Well, Medic made Heavy a giant Sandvich on one of the Christmas cards, so maybe you're on to something.
 * The Heavy from Nerf NOW!! recently got an upgrade to his Sandviches from an earlier storyline. Seems appropriate.
 * The Sandvich is a sapient sandwich who worked as a mercenary for the administrator. However because of his attempts to make friends in the battlefield, the Administrator decided to get rid of all that he loved and put him in the fridge, guarded by the blue Soldier and the blue Scout so he couldn´t escape. This was until the red Heavy got inside the base and ate him. Now he is getting his way out of hell to avenge his own death by killing the Administrator.
 * A bagel Spy.
 * Baguette, surely?
 * Related: Meet the Sandvich was taken from the perspective of the Spy's head in the Medic's fridge. It would explain why we couldn't see what was going on outside.
 * The tenth class. This is why it has its own 'meet the' video- Someone on the team secretly intercepted and killed the guy, making him into a sandvich to hide the body.

The Spy is....

 * ...“A Double Reverse Quadruple Agent …” In his old trading card bio, it says that the Spy “knows the byzantine details of who really runs things.” This may still hold true. He could be working as a double-agent for both RED and BLU while reporting to the Administrator… (he may have been the man who delivered her message to the soldier) but none of those could be where his true allegiance lies… so, just who is the Spy?
 * A descendant of Silas Mann?
 * A descendant of the unseen man?
 * The head of SpyTech Industries?
 * Working for any/all of the above?
 * Related: Miss Pauling is Spy’s daughter, and Scout’s half-sister. Spy took her in, taught her well, and relies on her skills as The Mole to be his eyes and ears at TF Industries.
 * Makani posted a drawing on her livejournal of Spy with dark hair- she's since been hired, so that similarity could well be canon.
 * Suffering from Chronic Backstabbing Disorder - Oh so very check. He's a "double reverse quadruple agent," after all.
 * Pyro's Twin Think about it. They have the same voice actor, and they happen to be the biggest counter/countered combo in the game. It's clear they hate each other from years of sibling rivalry. And if you want to explain the purse, maybe they both came from the same village Bridget was from, and Pyro was the designated girl.
 * Perhaps they were fraternal twins and the Pyro was a girl?
 * The purse is Pyro's attempt at a disguise, then?
 * A woman. It would be damn near impossible for a woman to be hired for an other-wise all male mercenary team in the 1950's and '60's, no matter how good she was at Spy-ness. The obvious response to being scorned in that fashion would be to invent a new male persona, get hired, and then spite your employer by never really being on their side.
 * Spy's certainly the only class to have tiny womanly—er, I mean, realistically proportioned hands compared to everyone else (including Scout)
 * involved in the project that created Agent 47. He's very likely bald, given the snug fit of his balaclava, he wears extremely well-tailored suits to the battlefield, and he assassinates people via infiltration and disguises. Sounds like anybody else we know?
 * A descendant of Altair Stealthiness, assassination skills, all that jazz.
 * Lupin III Why not? Lupin lived in the time period, is at least half French, and has a pretty good track record with the ladies. One or more of the other classes work for him as well.
 * Diabolik's teacher.
 * Ocelot * Revolver – check,
 * Glass Joe. Maybe connected to the Soda/Heavy theory . They're both french, have all the Defense properties of cheese, and quite honestly, who would ever suspect a meek feeble wuss like Joe of being a suave, sexy Badass who slept with your mother? There is a glass jaw under that mask...
 * Leonard Cohen Not only does he have the suit, but this troper worked for a Fancy Fedora just because of how much the ensemble fits Leonard Cohen. They both have gravelly voices that can make a woman wet. Cohen was born in Montreal, which could explain the occasional French words.
 * an unevolved Ditto. Think about it, the Spy can shape-shift, much like a Ditto, but only into 8 other forms, as well as turn invisible for a few moments. Also note that when he bursts into flames, he burns with his original color, which a regular Ditto wouldn't, and he cant use any of the moves that his other forms have, which a Ditto would be able to.
 * always crying in-front of rainbows. Rainbows make HIM cry, not Scout. HE used his deepest sorrow as a taunt for the scout.
 * Not actually French. He's just faking it to hide his true identity further, look cool, and pick up Scout's mother. In actuality, he has either a Bostonian, Texan, or whatever Pyro has accent.
 * Far less professional than he'd like to admit. Listen to his Un Evil Laugh and his juvenile insults. His classiness is well put on, but in the heat of battle it slips a bit.
 * The proud owner of a classy moustache. Frenchmen are often seen as posessing thin oiled moustaches. Maybe Spy has a Badass Moustache under his balaclava.
 * Of Arabian descent. His Saharan Spy set and Assassin's Creed promotional items lend some credence here.

The Spy's disguise really is nothing but a paper plate with a drawing on it.
And that is enough to fool the other team.
 * That's why it takes so much less time to put on a disguise compared to in TFC.
 * It's also why fire renders the spy's disguise completely useless; paper burns!
 * The other team all see it as such, they just pretend otherwise because they don't want to hurt his feelings.

That isn't what Spy really looks like
The balaclava is just so people assume that's his real face. In actuality he looks completely different, being a Master of Disguise. In fact, he may not even be French at all.

Pyro is Spy's equal because nobody knows anything about her
We don't even know Pyro's gender, let alone what she's talking or thinking about or her nationality. Spy's job is knowing everything about everyone, even to the point of taking pictures of his counterpart having sex, but he doesn't have the remotest clue who the mumbling freakshow who keeps outsmarting him is.

The Medic is…

 * a Holocaust survivor. He was born in Germany around the 1940's, but "He never was, and never has been, a Nazi." His bio also hints at a "dark past". During World War II, Nazi scientists occasionally coerced talented Jewish doctors to "help" them by holding threats over their families. His dark past: He helped the Nazis experiment on live innocent human beings because he couldn't bear to see his (daughter? son? wife?) hurt. . Perhaps the sheer depravity of the all the things that went on around him broke him, and transformed him into the sadistic Mad Scientist we see in the game. When the war was over, he knew he was too twisted to save - so he kissed his family goodbye and took up a new job, one in which his new proclivities would never be used against anyone save other mercenaries… Suddenly his drug abuse makes a lot more sense. Or maybe he himself was able to escape the Holocaust as a youngster by passing as a Gentile, but the rest of his family wasn't so fortunate, and one by one he saw his relatives hauled off to the ovens. Enough of these Break the Cutie moments combined with his Survivor Guilt from the inability to save his loved ones eventually drove him to insanity. His fondness of the violin is a memento from a happier time.
 * Possibly supporting the Jewish theory: Listen to "Archimedes" and tell me there isn't a Klesmer/Yiddish vibe going on.
 * A grown-up Klaus Baudelaire from A Series of Unfortunate Events, which also factors in Break the Cutie and Ambiguously Jewish. He's short-tempered because of his bad childhood. Think about it. He became a doctor because he's used to protecting his two siblings, both are very intelligent, Klaus is a German name, and he looks a lot like a young Medic.
 * Obligatory Time Lord suggestion: He's a doctor, but he has no known doctorates. He wears a long coat, and he always has Companions surrounding him.
 * Probably Jossed in Meet The Medic. He does have a doctorate degree, but his license to practice medicine was revoked.
 * Keith's grandfather. How can he survive everything that happens to him? Hereditary healing factor, of course!
 * A grown-up male version of the Little Sister. Dr. Tenenbaum tried to make a Little Brother, but his self-healing abilities were too slow-acting to be useful so he was promptly abandoned on the surface. When he grew up he got his doctor's degree and, using the invincibility powers of ADAM, invented the Medigun. Notice that he also has a preference towards being protected by big, tough, gun-wielding brutes... Sometime before the game, RED sent him back to Rapture to recover something of interest (possibly more of Tenenbaum's research) and ended up recruiting the splicer that became the Pyro. The artbook for the second game does mention the existence of "Little Brothers" as a deleted concept; in-universe, they were implanted with the same slugs as the sisters (possibly with similar abilities conferred), but apparently became too violent and destructive to be used as efficient gatherers. Hmm... he has their iconic weapon, the Vita-Saw…
 * Related Theory: Medic is Tenenbaum's brother. He lost track of his sister in the camps, and never saw her again. He had a medical talent and scientific curiosity to match hers, but as he grew more tortured and twisted by what he was forced to do, he grew to resent the altruistic behavior he remembered of her, becoming increasingly certain that she had been killed because of her naiveté … gradually, he began to suspect that his captors had the right idea….
 * Gay. Remember, the Nazi's most famous racial prejudice was against Jews, but they also sent gypsies, the mentally and physically disabled, and homosexuals to concentration camps. Thus, why he was never a Nazi, as he agreed with their views on human life, but not on gay rights.
 * Building off of that, he could have wanted to join the Nazis, but realized that their idea of a "master race" was stupid. His backstory in Meet the Medic will end on the heartwarming note of the lesson that he learned in his experiences: No-one deserves to be dissected for their religion, race, or ethnicity. People may be different on the outside, but they're all the same on the inside. Believe me, I've looked.
 * Alternately, Meet the Medic will feature the Medic playing a Violin while flashing to various things the medic has done. Bonus points for having the medic playing the Team Fortress 2 theme with himself making a commentary on his job.
 * ...A former colleague or student of Dr. Richtofen from Nazi Zombies. The Medic was secretly sent to work with Element 115 with him, but after Richtofen's disappearance (In other words, getting stuck fighting zombies with the very people he experimented on in various locations and scenarios) and the death of Dr. Maxis, the Medic stole their research on the element, worked out the problem of creating a Zombie Apocalypse, and used it to create his own Medigun technology. Given that Element 115 seemed to have healing or regeneration properties, it's plausible, and it can explain why all the other classes are so psychopathic- The Medic's continued use of the Medigun on them alters their sanity just like it did to Tank, Nikolai, and Takeo.
 * Unfortunately, as a side effect of working with him for some time, along with the possibility of being exposed to Element 115, Richtofen's own erotic (and insane) behavior completely broke the Medic's mental well-being, and turned him into the Mad Doctor we see now. They both obsess in causing pain, dislike their allies, and they're both more than capable of combat. Funny how they both ended up fighting alongside a Russian and a psychotic American soldier. Though.. how the world managed to quickly recover from the zombie infestation as though nothing happened is anyone's guess.
 * Never joined the nazis, nor was he ever sent to the prison camps. Despite being a jewish doctor, most of the people in his village knew his as "that crazy bird man". He made sure the people of his village knew about his experiments with non-bird animals so they would be frightened away. He also trained his birds to attack villagers he didn't like, and bring him their organs for further experimentation. He did run a small clinic, but the people would only go to him as a last resort due to his unorthodox methods and the fact he let the birds in the operating room. When WWII rolled around, Medic was the only jew left in town. Some Nazis came to his house and demanded that he care of an injured comrade and they wouldn't send him to the camps. Not trusting them, he packed up all his birds and tools, stole the patient's skeleton as a "trophy" and got the hell out of dodge.
 * Was never a "human" doctor to begin with. He's a veterinarian. With a specialty in birds, but he also dabbled with other animals. When so many doctors were shipped off to treat all the army injuries (Medic got out of it by proving to be deaf in one ear, or some other minor injury), Medic was left to take care of animals and people.
 * the Civilian. Meet the Medic's timeframe is set just as he joined the team. The Heavy, The Scout, the Engineer, the Sniper and the Demoman were originally assigned to protect him so RED could gain exclusive access to his research. The BLU mercenaries, meanwhile, were looking to capture him to make use of his research. Both teams had the goal of finding a way to extend their employer's lifespan further, and the doctor's research in healing chemicals and an efficient way to disperse them was just the right lead to follow. The BLU team, not particularly frightened by the Reds, sent out a team of Soldiers to overwhelm them and take the Civilian to Blutarch. After the Civlian and his bodyguards are cornered in a hospital with ample supplies, he decides to make himself useful and act as their behind-the-lines doctor. However, when Heavy comes in with a chest ripped open by a rocket that never went off, he sees an opprotunity that changes his life forever.
 * The Medic isn't Jewish, but his career stalled out during the Third Reich because his particular brand of Mad Doctoring wasn't in accord with Nazi ideology or one of his grandparents had a non-Germanic last name. Out of spite, he joined up with a group of resistance fighters, and became the first person to perform a heart-lung transplant outdoors during a Central European winter, among other accomplishments.
 * Formerly employed by HYDRA. After all, the Nazis could be so tediously dogmatic about their political ideology, often to the detriment of scientific progress.
 * Originally from East Germany, and a practitioner of Soviet Superscience. Why else would The Heavy, who's probably old enough to have seen the results of Nazi occupation firsthand, be prepared to work with him?
 * somebody not even the Nazis could stomach. His inhumanity was so great that even Hitler's goons had a hard time dealing with him, and sent police officers after him to catch him and execute him. That, or they didn't appreciate his abduction and dissection of their personnel, especially the Aryans. The Medic is good with weaponry mainly because he had to outfight the Nazi police, and his captives, if the aforementioned dissections actually happened.

The Mediguns are less "Medicine Guns" and more of an "Immune System Overclockers"
I'm mostly basing this on the use of the word "Voltage" when the Medic is talking about using the Uber device on the Heavy's heart. We all know that our brain send electrical signals to the rest of our bodies to tell it to do stuff. It's not too much of a stretch that the Medic designed a gun that speeds up the use of the "Fix the broken parts" signals or something to that effect. This overclocking also allows the patient's body to work harder than normal, allowing their body to take more bullets than normally possible (Overheal). Each respective Ubercharge is the result of each of the Medigun's use of amplifying the voltage.

Medigun: Amplified voltage is unleashed unto the Medic and their patient themselves, along with their brain signals. This also (somehow) makes an outward magnetic affect that nullifies bullets, rockets, etc. Stuff like the sandman's baseball are also worthless due to a physical shell that the charge creates with the voltage, explaining why the characters become metallic looking.

Kritzkreig: Amplified voltage flows directly to the patient's arms and weapons. Melee attack become crits because the patient's brain is sending stronger signals to the swings. Guns shoot crits because the voltage melds with the bullets, so you are essentially shooting electricity. This happens at random due to residue voltage left by the mediguns when they heal normally. This medigun charges its uber quicker due to not needing less voltage as it is only directed at the patient's hands and what's in them.

The Quick-Fix: Word of God claims that the first Ubercharge made by the Quick-Fix shorted out its Uber device, so it can't be recreated with this medigun. As a result, the Medic tried to see what he could salvage from the old proto-type a few years after he had made the proper Medigun designed to withstand the Ubercharge. Instead of overclocking the healing system to the point of overheal, Medic tried to see what else he could manage with extra volts. The result? The ability to speed himself up so as to keep up with the Scout, faster overall healing, and a quicker Ubercharge fill. The ubercharge puts a magnetic barrier around his and his patient's feet, keeping them from being blown away or slown down. It also makes the healing 300% more efficient, but not strong enough to create an overheal.

The Pyro is…

 * Hank Hill. His flamethrower contains propane and is made out of propane accessories. Him and Engy get along so well because they're both hard-working Texans. I tell you what.
 * Kenny all grown up. He speaks with muffled unintelligible dialogue which is often hilarious when heard, he gets killed constantly, and "setting people on fire" is totally a job Kenny is crazy enough to take. Also because someone had to say it.
 * Abraham Lincoln. The Previous Pyro, a life –extender machine is known to have been in working order the day he died in a tragic rocket jumping accident, the sort of incident where, if one could survive it; they would still be terribly scarred and maimed from their burns. Radigan is documented as having been working on a machine to save his life. Pyro’s feminine behavior is, as such, easily explained: Since Lincoln’s actual real-life death, rumors have swirled about his sexual orientation…
 * Adam and Jamie Hyneman Adam is already a Pyro. He required no convincing to sign up for the job, and approaches it with child-like glee and enthusiasm. However, he didn't anticipate that no one would ever be able to understand him, and he's been driven (more) insane from loneliness. Jaime required more convincing to accept the job, but he's quite good at it. He, unlike Adam, was naturally suited to being a Pyro, and he excels at it. He spends his time thinking and coming up with creative and painful ways to kill his opponents using their surroundings. W+ M1 are Adam, and more skilled Pyros are Jaime. Also, Kari is the Engineer's daughter. Compare Kari and Engineer.
 * The Pyro being Adam explains the love for hats.
 * As of the episode "Fire and Ice," Jamie has constructed his own homemade flamethrower, and both of them have been in fire retardant suits that obscure their individual identities, but allow for gestures, pantomiming, and in Adam's case, gratuitous dancing.
 * The Pyro is a construct similar to a Big DaddyThe Pyro is neither a man nor a woman (though it was once was at a time). The subject went through the same process as a Big Daddy and was turned into an efficient soldier. This is why the Pyro is never seen without their suit: it's their skin.
 * Hanz from Pumpkin Scissors He's so cold. But he's warm when other people burn. :3
 * Vaarsuvius. They're both ambiguously-gendered people fond of explosions and fire. That's all I got.
 * Gabe Newell. "And my favourite class is the spy." But of course, it's your easiest target!
 * I don't think he could fit into that flame-retardant suit very well.
 * an Energy Being He comes from an alternate dimension where everyone is a gaseous Energy Being, and made the firesuit to prevent himself from dispersing. (Something in his home universe prevents him from dispersing there.) His species is highly flammable, and because he's insane, he's perfectly willing to use a weapon that could conceivably destroy himself. Because he's not quite that crazy, though, the suit is fireproof. Getting shot tears holes in the suit, causing small parts of his substance to disperse. The suit has internal repair systems that seal the gaps and stop him wafting out completely. The power sources for these systems are located in the head and back, which explains why the instant kills work (the transmitted shock takes out the other power source).
 * Actually deaf Taken from jpqfd's comment on this video. "Pyro is actually deaf so that's how he keeps his calm the whole time while burning people. He can't hear the flaming, the screams, or the bullets flying. It's all peaceful and in harmony." Because when I heard that, it all made so much sense. The laughter is actually him thinking he's won some game that the announcer invented for him, and the gas mask obscures everything he sees. He just knows he's supposed to "win".
 * A Fourth Wall Observer. Pyro doesn't think it's a game because s/he's an Innocent Inaccurate; Pyro thinks it's a game because it's a game.
 * He keeps everything about himself a secret in order to to screw with people, hide as another masked character in an entirely different fictional work if need be, and prevent anyone from ever creating completely accurate Rule 34 of him.
 * incapable of feeling pain properly. This struck me while I was in an idle server. I noticed the Pyro's flinch when taking damage was far less noticable than most others, and simply a repositioning of the elbows. Then I realized the Pyro's grunts don't even play that often when under heavy fire. This is why most classes are afraid of it. It's a ground troop that defuses most Spy efforts, can decimate ambush forces, plow through most defenses, overall ruin an organized plan, and it won't even so much as wince when shot most of the time… and he’s probably covered in third degree burns
 * Alternately, he’s in constant pain. Same reasoning as above, but also gives an excuse for the "harmless friendly fire hurts opposing Spy" tactic: Pyro pyrizes indiscriminately because s/he thought the flamethrower was below everyone's baseline of pain (see also the WMG that Pyro thinks it's all a game, under "the pyro is actually deaf" above), and his teammates are used to it by now which reinforces the idea. The Spy for your team is not used to it from being disguised as an opposing team member and needing to stay out of the fire to keep cover, and/or RED and BLU use different chemical propellants that each have additional damaging side effects (since opposing team members are still affected by your team's flamethrower and vice versa).
 * Pyro has no immune system. You just never see hir running to a hospital to be put on masses of antibiotics and antivirals after the suit is damaged because none of the battles last more than a couple of hours.
 * Pyro is a Quarian. Building on the "no immune system" theory above, it is entirely possible that the Pyro has a weak immune system because he isn't even from this planet. Unfortunately, some aspect of his arrival crash-landing damaged the synthesizer that most Quarians seem to use in order to be heard past their masks, leaving him unintelligible, if he's even capable of speaking English. He's playing the in order to get enough to repair his craft and return to his flotilla.
 * Pyro is a Decapodian. The Pyro uses the suit so as not to get dehydrated from using the flamethrower, and his/her voice is muffled by the facial tentacles being wrapped around an oxygenator in what would for a human be the air filter. This is why the Pyro has a Brain Slug hat, various silly props, and acts in such odd ways: He or she is a Decapodian prop comic.
 * The Pyro is Keith. Like Keith, the Pyro has extensive experience in starting fires and making them much worse. He spends all his time in a full-body suit, which is an excellent idea if you're in the habit of recieving third-degree burns over 95% of your body. The Pyro also seems to be relatively unfazed by life in a constant warzone, a trait you'd expect in a man who's cheated slapstick death numerous times and survived being bombed by the army. Given his previous work history, being a flamethrower-wielding mercenary is probably the closest Keith's even been to having a steady paycheck.
 * The Pyro is Mr. Bean Try to imagine the how the Pyro would handle everyday life. Would it look anything like this?
 * a primitive Cremator Pyro burns people, leaving behind corpses if (s)he's good at his/her work, wears a gas mask, and nobody really knows what the Pyro is like. Cremators use flamethrower-like weapons to dispose of people in the Half-Life 2-verse and are never seen, so nobody really knows much about them, either. Cremators also appear to be at least partially trans-human. The Pyro is merely a prototype, explaining the home-made appearance of the flamethrower and the combine-esque gasmask, since Cremators were to use weapons that essentially burned enemies away.
 *  Scout’s Mom.
 * And the Announcer is Scout's Gran. It works.
 *  Miss Pauling Here is Miss Pauling, seen with the Administrator. Look at the Saxtonette on the right. See a resemblance?
 * A mecha, built and piloted by The Engineer's daughter. She's obviously inherited her father's Mad Scientist tendacies, given the homemade weapons, and what kid wasn't into sci-fi back then? All of her weapons are designed to help daddy with his work - there's one that reveals spies and reflects grenades, one that removes sappers, and one that stops snipers from aiming. The glove was a gift from her father rather than a trophy, and she acts like a Psychopathic Manchild because she is a child. She has a device that makes her sound like a man because she knows her father wouldn't want her to be out on a battlefield, although he may already have his suspicions ("didn't yer mama teach you not to play with matches?").
 * Alternatively. Pyro is a Robot Pyro is a cyborg or robot created by the engineer (some of his eleven PH Ds could be in biological or robotic engineering), possibly as a prototype for the Manns, as transferring their brains into robot bodies would be an easy way to appease them while Dell could keep the life extender machine's blueprints for himself. The suit actually IS the Pyro's skin, and beneath the eyes of the gas mask are cameras, possibly in infrared. More evidence for this theory can be found in Meet The Spy: (One of the possible messages on the alert screen is The Pyro is/a Robot,) True Meaning, (Dell lives with Pyro) and The Foundry map: There are photos in the RED team's room on Foundry, and a prominent bloodstain in BLUs. 1961 is the year the Unimate robot was first installed on an assembly line, while the neatly divided sectioned word fragments in the sign reading AUTO-BORAX spell "ROBOT" backwards. While we're on the subject, guess who uses the ax?
 * Perhaps Pyro was a joint collaboration between two friendly mad geniuses.
 * It's an interesting theory, although why Dell would program a robot to have a habit of wearing women's clothing just raises further questions, unless he's still working out the kinks in the AI.
 * Maybe brain uploading played a role.
 * A cisgendered woman. Hinted at by the in-game character bios plus the fact that no one could tell what is going on under that flame-retardant suit. What clinches it for this editor is the purse in Pyro's locker. Next time you spawn in the game, check it out. The lead developer of TF2 referred to the Pyro as "her" in this interview. The Pyro's standing pose after losing a round seems very feminine, and one of the Spy's domination lines toward the Pyro says that the Pyro fights like a woman. As to her voice, everybody's voice sounds masculine when you're talking from behind a face mask and a air filter. Besides, you try inhaling asbestos and ash for X+ years, making explosives and not, and see what your voice sounds like. The helmets are "trophies" from soldiers said spy successfully backstabbed, much like how many soldiers collect mementos from their kills (Manfred "Baron" von Richthofen did this, for example) Obviously, the gasmask and muffled voice are all part of a Sweet Polly Oliver gambit. Maybe we have some case of Samus Is a Girl here? And The Pyro's new weapon? The Homewrecker...
 * Relatedly: The Pyro may have decided to install a voice filter on the mask because she knows that otherwise all the guys on both teams would constantly be jokingly hitting on her and it would get annoying. (Oh yeah, plus the all-male mercenary group in '68 thing below, thank you).
 * Alternatively: the Pyro is Doctor Girlfriend.
 * A gay man. He's a flamer.
 * A lesbian woman.
 * a ghoul created by the Announcer. Ghouls can't speak and have limited intelligence, but can operate weapons. The Announcer never goes outside (notice how many of the stages are set during the day?) The rubber mask is so the Pyro's teammates don't notice that he's an undead monstrosity and stop healing him. The Announcer turns all of the casualties she can into more Pyros and eventually will be able to attack Redmond and Blutarch, who have been turning the others into freaks with a taste for bloodshed.
 * Well how many does she need? Everyone's died at least a million times already!
 * A soul bound to a suit, a la Fullmetal Alchemist
 * Then how does one explain the suit and mask hanging in the locker room?
 * Backups.
 * A Mutant Mole Man It was smart enough to figure out how to use fire to fight back against the Children of Ishtar without hurting itself. The suit's there to hide his deformities and protect his own sensitive eyes; it also hides the fact that the mutants seen in the movie can't speak human languages (most just blame it on the mask).
 * A cisgendered male trickster. This heavily relies on his unlockable hat: the beanie. Back in ye olden days, the beanie was used to represent a trickster or someone who was very childish. If he were a trickster, that would mean that the only reason he owns a purse is for the sake of the pun that he's flaming. He's so childish that he doesn't care about the implications, as tricking everyone else into thinking he's a woman or gay would be right up his alley. If you pay attention, he also seems to use the same few speech clips, even in completely different connotations (the same voice clip for his battle cry is used when he dies and when he charges up a Hadouken). He does this to try and trick his teammates into finding some sort of pattern in his muffles when there is none. He's even more of a Magnificent Bastard than the Spy, which is why he's the bane of the Spy's existence.
 * Alternately, Pyro's a woman playing up her feminine gestures to tease people into believing there is a possibility she's a woman when they wouldn't have even considered the thought beforehand.
 * …an infected. Or a zombie, if you prefer. The muffled grunting, the shambling gait, the complete lack of any self-preservation? (S)he'd be gnawing on brains right now, if not for that pesky gas mask (or not).
 * a Splicer. The Pyro managed to escape Rapture and get work as a mercenary. Though his physical deformities are covered by the suit and mask, her mental deformities brought on by constant splicing are still quite present. For instance, he's obviously quite brilliant with inventing things (both her flamethrower and the chemical thrower appear to be cobbled together from scrap metal and plumbing parts), but he is also sociopathic, having no remorse for burning others to death and even taking joy from it. It would also explain the Pyro's "Hadoken" taunt- it's actually an Incinerate plasmid.
 * a highly intelligent jerk. Listen to clips of his voice after reading the probable translations on http://wiki.teamfortress.com/ . You'll notice that he sounds extremely condescending all of the time, and everything he says that's directed at other people is basically * instruction* * insult* . And not like the Soldier's "GET ON THE POINT, NUMBNUTS". The Soldier sounds angry, but the Pyro just sounds like he's tired of having to explain everything to people.
 * of Asian descent His voice clips seem to put emphasis on all the wrong words, kind of like a badly dubbed Japanese movie. Considering the horrible accents of the other foreign characters, this might not be too far-fetched. It might also explain why others refer to him as a "freak" - relationships with Asia weren't exactly nice at the time, what with Vietnam and Communist China and such, so people will go out of their way to make fun of/taunt/abuse the poor guy. That would explain the Spy's hatred for him (before turning communist Vietnam was a French colony)
 * Fridge Brilliance- the characters of the Team Fortress 2 world are based on national stereotypes, like the German mad doctor and the angry Scotsman. The stereotype of the inscrutable and silent Asian wo/man would fit nicely.
 * a highly intelligent Vietnamese man. He's just screwing with his teammates. The BLU pyro is Jessica from the mac update comic.
 * Zoey Zoey wears red and blue and she could share the same gender as the Pyro. That's all I got.
 * is Pyramid Head He wears an intimidating outfit, we never see his face, and the only people who actually see him are killers. Also, his weapons are all fire based, symbolising the original fire and Alessa's subsequent injuries. The act of spy checking is essentially forcing players to admit to whatever actions led them to this point. The reason it only affects spies is because they are the only ones trying to deny their actions. It also explains why the other characters consider him a freak.
 * an extraterrestrial. A classic 60's Little Green Man or one of The Greys, natch.
 * Maybe... *sniff* maybe.
 * Dr. Salvador The only thing missing is the chainsaw.
 * Matt Helms After Travis killed him, he made a Deal with the Devil (Again) to be resurrected to get revenge on Travis. however, while being resurrected, he accidentally went back in time to the 1960s. In order to pass the time until Travis was born, he joined the war between RED and BLU.
 * Hansel and Gretel
 * Spanish - if you listen closely to the lines they do sound slightly Spanish.
 * He does have a few rather Spanish/Mexican hats, like his day-of-the-dead sombrero.
 * The Engineer At some point in the future, the Engineer builds a time machine and uses it to travel back to the present. The reason he wears a mask is so his past self won't recognise him. The flamethrower is just because he hates spies so much.
 * The Worm That Walks Under that suit is not a man, a woman, or a machine! It's thousands of small animals, which may be rats, reptiles, bugs.... Or, if Pyro is a robot, it's controlled by some sort of rodent or rodent-sized animal, or a pig in a suit.
 * Sentient, hive-minded potatoes.
 * Psycho Mantis Think about it, they both wear gas masks, they both like to kill people and Pyro's hat indicates he might be a psychopatic manchild. His Pyrokinesis has taken a hit though (being limited to one small flame, albeit one that seems to instantly cook the insides of whoever it hits).
 * a Genre Savvy / Paranoid Spy He's noticed how easy it is for a spy to be discovered, and went the extra mile to trick the enemy, by creating an entirely new person out of himself. The reason he doesn't sap any sentries or backstab anyone during the game is because he's just that worried about being caught, and the reason why he can walk through the enemy team is because he is wearing proper uniform. That's why the mask hides his face and his voice, a spy is under there and when the game ends, it doesn't matter who won, because the Pyro has.
 * The Joker Some men just want to watch the world burn.
 * a unknown species of Pokemon. The Pyro is an unknown fire-type Pokemon capable of using Gust (the compression blast), and he can only say his name (the blured sounds are actually him saying his name in a lot of different ways).
 * Spyro He likes fire and his voice/face are muffled. It could be, you never know!
 * The Spyro is a pie! The pie is a lie. Therefore, every Spy as a Pyro is actually a dragon dressed up as a man dressed up as a robot dressed up as a woman dressed up as a man. I Knew It!!
 * Word of God is that The Pyro is… The Pyro. All of the above?
 * Spyro's mother/father! Spyro is purple (red+blue) and breathes fire!
 * Oh, you mean like this?
 * A Platonic Ideal. The Pyro does not have male or female attributes. Males and females have Pyro-like attributes. The Pyro is, as above, the Pyro.
 * A time-displaced Doctor Who fan. Easy enough to figure out- wanting to save the wiped episodes, a geeky Doctor Who fan built his own time machine to travel back and record the episodes before they were destroyed. However, his machine was faulty and he got transported back to the start of the sixties, three years before it even began. His machine broke, and now he's taken a job as a masked soldier of fortune to support himself and get the funds necessary to repair his time machine. All the pop references are because he's such a geek, and handily explains why he can reference Star Wars and Street Fighter before they were created. He occasionally acts like a woman because he has fun screwing with the rest of the team's heads. Oh, and he's also British. The Pyro's muffled voice clips sound like he occasionally calls teammates "mate," and we've already got an Australian, so...
 * The Scout's older brother. He was enraged when he found out how his younger brother came about and, wanting to avenge his brother, became the perfect antithesis to the skill set and combat style of his father in-law, the spy.
 * Bruddah also rhymes with Huddah. Food for thought...
 * Calling for his Daddy. "Hudda" could be a muffled call for his parent. Yes, the Pyro is a Gas Mask Zombie. The suit is to prevent him from infecting his team.
 * Pre-op transgender. Pyro hides because s/he doesn't want his/her teammates to see him/her in a body that doesn't suit them. Alternately, an intersexed individual who wants to avoid confusion from their teammates.
 * Chinese. It'd fit in with the time period (escaped from the Communist regime, perhaps?), and China is usually associated with fireworks and dragons.
 * Which might explain his/her rivalry with the Heavy.
 * This would also make the first BLU Spy being Fu Manchu rather amusing.
 * Japanese. The Hadouken for one, and because it'd piss Soldier off, for two.
 * This is why they're so good at finding invisible assassins- they practiced on ninjas growing up.
 * A Jewish survivor of the Holocaust. He was severely burned in one of the 'ovens' of the death camps, and wears the fireproof suit to protect himself and hide his deformation. He also hides a Star of David under the suit. (I like Respawn of the Dead, sue me.) This explains his "rivalry" with the Medic - the best counter for afterburn is the Medigun, after all.
 * Black Mage. In that case he would have a good reason to hide his face.
 * A furry. (S)he knows all to well that if his/her true nature was discovered they'd be burned alive, because everyone on the internet hates furries. Fortunately, (s)he found a costume that covers up all the animal attributes.
 * Either Five from Generator Rex, or an earlier relative of hers.
 * Think about it; she can take ridiculous amounts of punishment, has a thing for close combat, rocks out on a close combat weapon, and is British. When combined with the lack of british on the team, and the British Pyro theory, it makes sense.
 * The suit is to hide the fact she is female, and it prevents her from doing crazy backflips, but she still plays rad air guitar, and charges into impossible situations utterly sure of success or oblivious to defeat.
 * The fire would tie into the ancestor theory. The previous incarnation had a thing for fire, the next one is a punk. Actually, the Pyro can be a punk, too.
 * An internet troll. He lights fires in the chat forum by being a complete demonic spider, upon meeting an enemy pyro they often start flame wars, and the Flare Gun is an irritation weapon because he cannot stand lack of attention for too long. The homewrecker destroys anything an eingineer he doesn't like can come up with, the Axtinguisher silences those who have already been set ablaze, the Third Degree hits people trying to assist his enemies, and the reason you don't understand him is beause he speaks in Insane Troll Logic.
 * Saxton Hale.
 * Severely Autistic.
 * Deadpool. Marvel once did a one-off story which put forward the idea of an alternate, WW 2 version of Deadpool. A soldier in WW 1, he was forced to wear a gas mask at all times due to smoking his lungs to hell and back, and his mind was shattered by lack of human contact and spending every penny on budget rubber-hose cartoons. At the height of the Great Depression, he was tricked by German spies into undergoing a flawed version of the operation that made Captain America. It gave him the strength and speed of Cap and a healing factor, but it set him on fire and the scars were so bad the researchers decided to never try the operation again. Called "Veapon X" (with the X stylized to resemble a swatstika), Deadpool was deployed in the field but had a change of heart and decided to go AWOL for the rest of the war. He was never heard from again.
 * A former Valve employee. Some habits from his old job stuck, and without a userbase to troll, he can't resist messing with his teammates' heads.
 * A four-year-old girl with no idea what death even is yet. The Pyro suit is Powered Armor. This ties into the guesses that the Pyro is a cisgendered female, thinks the whole thing is a game, and includes mechanical components.
 * A clone of the original Pyro, Abraham Lincoln. Unfortunately, due to the Pyro being blown to chunky red gibs repeatedly, the cloning agency had to cut a few corners. Namely, the Pyro is insane (the cloners don't have the time or money to make each clone a rational human being), the Pyro has no set gender (usually male, due to Lincoln's DNA, but sometimes something gets flipped and the clone is female), the Pyro has a rapidly decaying outer skin (he/she/it can survive for a few hours outside the suit before he/she/it starts to break down. Again, not enough time or money to make each clone stable.)
 * Pyro is Medic's wife. Er...them possibly sharing a gender, Heavies dominating them often and Pyros being good ubercharge candidates are pretty much all I got here.
 * A pair of Twins. One boy, One girl. They keep switching teams in secret, so that's why Pyro is sometimes referred to as a "she". The male half of this pair is gay, but his sister is straight. Either way "Pyro" likes men.
 * Jessie and James of Team Rocket. They botched a mission even worse than usual, and Meowth was killed as a result. Neither could take the loss of their friend and they both snapped, Jessie moreso than James (meaning, James became a sociopath, and Jessie went absolutely batshit insane.) Burning everything in sight is their way of coping with their failure and loss. W + M1 Pyros are Jessie, and more savvy Pyros are James. They also take turns on the battlefield; that's why the Pyro is referred to as "he" and "she".
 * The engineer's daughter. It would explain why the two work so well together, and why Engie was reading Pyro a story about Australian Christmas in the Christmas 2011 comic.
 * Engineer's retarded brother. The fact that the head is so tiny is more than indicative of a serious mental disorder. Though he has the body of a man, he has the mind of a child, which explains his affinity for silly hats and why his battle cry seems to be "Hello!!!". When Engie was recruited, He begged them to hire his brother too. Fortunately, "Dolt" really enjoyed setting things on fire. So Dell built him some equipment and set him "Out to play".
 * The Pyro is covered in severe burns, perhaps cheerfully self-inflicted. If they destroyed his nerve endings this may overlap with the above 'Pyro feels less/no pain' theory above.
 * Related to Freddy Krueger. He wears the suit to avoid being set on fire like Freddy, and if Scout is any indication he also likes killing teenagers.
 * A universe-displaced firebender, quite possibly Princess Azula.
 * If Pyro could speak, most of his lines would be cooking puns.
 * Someone who hates sandviches for no reason.
 * Pyro is actually behind everything, and pretends to be a ditz so no one suspects him.
 * The Pyro's full name is 'The Pyrotechnician''. He doesn't use it because he can't pronounce it.
 * Pyro has a supreme ego complex. Note- he's not 'The Pyrotechnician'. He's just The Pyro. He is fire itself.
 * Rorschach, who is masked and once used a flamethrower. Dr. Manhattan teleported him to this universe at the end of Watchmen, (feeling this time period would be most familiar to him), and he is acting far more feminine than is usual to compensate for his previous misogyny.
 * ...from Transsexual, Transylvania. Admit it, this makes sense.
 * Pyro is secretly the cameraman for some of the more gore-splattered parts of the Meet the Team videos. This is why his video is coming last- they couldn't find anyone crazy enough to replace him when he announced he wouldn't be able to shoot Meet The Pyro for some reason.
 * Someone from the previous generation(s) of the team (possibly using the life extender, though not Lincoln)- either as his/her speciality, the Pyro or as a different class entirely. This explains why s/he's fond of Engineer- s/he was best friends with Dell's father, or maybe even...
 * The Pyro is British. This explains his antagonism with the Spy, and a few of his classier hats. Underneath his mask he sounds amazingly sophisticated. Also explains why he doesn't seem to have much of a reaction to pain (see above).
 * The Pyro is the woman who offered Australium to Radigan Conagher, using the third life-extender.
 * President of, or at least a heavy influence, behind Spytech(see Loose Canon folder). She deliberately secured the company to supply her favourite prey with inferior equipment.
 * ...Of mixed nationality. This is why his hat collection is so varied in countries and his nationality isn't quite as in your face as the others.
 * A Black Scottish Cyclops.
 * The Firebat from Final Combat. What better place to hide/spend your free time than as your own ripoff?

.... A Time Lord

 * Rogue Time Lords love taking on titles that begin with 'The', such as the Doctor, The Master, The Rani, etc, and the Pyro just happens to have found a perfect place where no one will notice the odd habit, as everyone does it. As for the Pyro's sex/gender, its been changing constantly, along with its overall appearence, and we haven't noticed because of the clothes.

The Pyro's real name will be revealed in a comic.
It will be unisex or obviously fake, because Valve are trolls and want to keep us guessing.

The Sun in a Form You're Comfortable With.
The Sun needed a host body to keep certain people heated. However, it had no idea about humanity and that explains all the weird actions. It wears a mask and thick body suit to protect those around it but that doesn't stop it from using other flame related abilities to defeat RED or BLU.

The Pyro is a literal 'Frankenstein of a Man'.
Pyro is a gruesome creation of The Medic, made out of graverobbed corpses and the brain of a delusional pyromaniac. Underneath the suit, she is hideously mismatched and quite possibly rotting.

The Pyro is Radigan Conagher.
Using the third life extending device. He uses a flamethrower to protect his grandson from spies, and puts on a flamboyant persona so Dell won't suspect who he is.

Discord.
He escaped a second time, but knew the mane 6 would imprison him again if he spread chaos in Equestria. He crossed dimensions to our world and manipulated everything, including the formation of RED and BLU. He now roams the battlefields he has brought into being, incinerating all in his path and reveling in the glorious, beautiful chaos he's creating.
 * Or Pyro is Pinkie Pie off her meds.
 * Alternately, a Discord-assisted Firecracker Burst. Or Derpy!
 * RED Pyro is Discord and BLU Pyro is Nightmare Moon!
 * Screwball. She even has the propeller beanie!

Pyro is one of Lady Gaga's grandparents.
I'm guessing grandmother and Engineer is her grampa.

Pyro is The Dreaded, both by the other team and her own
Flamethrowers are usually used as a method of psychological warfare, so it would fit. It's why she hasn't showed up with any of her team mates in the canon(save Engineer) doing anything other than lighting things on fire/being part of the ensemble cast- nobody socializes with her, because she creeps even them out. Not without good reason.

The Pyro can speak perfectly well, just chooses not to
His/her bio states that his lungs are ravaged by asbestos, and that is part of the reason he talks unintelligibly. But Asbestosis and similar lung afflictions cause breathlessness, and yet Pyro is one of the faster members of the team. So perhaps that's just an excuse and he's shy, or hates talking to people, or thinks it's funny, or maybe he's hiding something.

Meet the Pyro

 * The video will consist of all of the Pyro's teammates talking about him/her in voice over, his/her insanity, how he/she screws around with them… while we are treated to a of a POV Oner shot from inside the Pyro's mask... as all of the BLU Team burn to death. Expect plenty of Shout Outs to classic horror movies- The Shining especially. The Spy will know exactly who the Pyro is, he will even have photographic evidence (see Meet the Spy), but he won't be able to reveal it: the Pyro will shoot a flare through the file. The movie will end when he (or she) begins to take his/her mask off.
 * The soundtrack will be rock or heavy metal. S/he does play air guitar as a taunt (also, the Third Degree’s guitar riff), and the pyrotechnics would fit nicely with it.
 * It will be a Mook Horror Show, in the slasher vein. And Scout will be the Final Girl.
 * BLU Spy’s head will be somehow removed. He seems to be having bad luck that way.
 * Pyro will actively troll the audience about what’s under his/her mask. Or, in universe, the camera crew.
 * It will be another interview film. But Pyro being Pyro, it will fail hilariously.
 * Pyro will find Spy via awesome detective skills, a cutscene version of spy-checking. BLU Spy is capable of being harmed by his own teammates in Meet the Spy, so maybe they’ll want to keep it consistent in-universe.
 * Kinda Jossed, when the actual "Meet the Pyro" came out at last.

The Pyro is Makarovin disguise.
Yuri and Price didn't really kill Markarov, he faked his death. He's adopted a new persona—that of an effeminate/childish pyromaniac—as part of a revenge plot against Yuri, Price, and the Russian Loyalists. First, he must find and kill Saxton Hale...

Pyro's appearance in Killing Floor was canon
Her yearly vacations consist of buying Doctor Who merchandise and killing zombies.

The Pyro's gender depends on the team S/He's on
The Red Pyro is the female Pyro and the Blu Pyro is the male Pyro.

The Pyro is a man who looks like a woman.
So he covered his face with a mask. His appearance still haunts him.

The Pyro has a pink purse because he CAN have one.
Who would be fireproof enough to question his taste?
 * Corollary: Nobody is quite sure if their team's Pyro is a man or a woman, but since walking up to a mouth breathing freak of nature and asking what gender they are has the potential to go badly they decide they are better off not knowing.

The RED Spy broke character before he dropped the act.
Specifically, when the BLU Spy revealed the pictures of him fucking the BLU Scout's mother. That wasn't a son finding out his mama was sleeping with the enemy.

It was a secret lover caught in the act.

Thankfully, the others thought it was the BLU Scout shocked and embarrassed about the pictures, so he managed to avoid blowing his cover.

Wait a minute... Scout's Mom...
Let's think about this for a minute, the pictures of her in Meet the Spy show her as incredibly young and hot. And she's the mother of nine children? Of which Scout (maybe 16–18 years old, at the youngest. But probably more like 20) is the *youngest?* Either she started having babies at a really young age (like 15 or so), and reeeally went out of her way to stay in shape, or there is something going on here... anyone have any theories?
 * She could have had Multiples on one or more occasions. It's a lot easier to reach eight kids if you pop out three in one go. Maybe Scout was the only one of her Children who DIDN'T have a twin.
 * Of course he has a twin, there ARE two scouts aren't there? The third one is an intellectual in college, since his brothers picked on him in their youth since he was more interested in reading than baseball.
 * The picture could be from before the Scout and his brothers were born.
 * And Red Spy is actually Blu Scout's father. The images could possibly be Scout's conception.
 * Nope. Word of God has confirmed that the Spy is NOT the Scout's father.
 * Perhaps some of Scout's brothers are adopted.
 * The Scout seems to be from a lower-class family, which would support the theory that his mother had many children at a young age.

In Meet the Spy, the RED Spy was actually the BLU Spy with a dead ringer.
The RED Spy also had been using Eternal Reward to disguise himself as the BLU Spy. Once he was killed, he snuck around and stabbed the Scout, disguising himself as the Scout.

During the Meet the Spy video, both Spies were working together.
The BLU Spy was secretly a double liver gambit.
 * It's no secret that Spies are far from trustworthy. (See his conversation with the BLU Scout.) Notice how he goes on this extensive rant on how incredibly dangerous the enemy spy is...right after he  a terribly dangerous thing to do in such a situation, even if he  The explanation was that he was planning to defect to the other team and hoped that the RED Spy was in the room. In a way, the Soldier was right.
 * In addition the BLU Spy had a Dead Ringer equipped, which is why he was so easy to kill, and he escaped using his invisibility after the Soldier blew his cover.
 * With the new Polycount items, something else is also possible in that it's just the same spy with 2 knives. BLU Spy is RED Spy, using a Dead Ringer and Your Eternal Reward. After getting "killed" by the Soldier, he runs off, decloaks, Uses Eternal Reward on BLU Scout, then gets his regular knife back.

In Meet the Spy, the BLU Spy knew the Scout was the disguised RED Spy all along.
The BLU Spy knows that he's on the losing team. He decides that, in order to send a message, he has to defeat his counterpart in a particularly embarrassing fashion. To start, he out-Spied the Spy, catching him mid-coitus. The woman wasn't actually the Scout's mom (does she look like someone who's had 8 kids?), but the BLU Spy showed the pictures to the RED Spy in order to let him know that he had been outplayed. The BLU Spy claimed that she was the Scout's mom to psyche him out without blowing his cover (the BLU Spy wanted to watch his doppleganger squirm for a bit). The recounting of the RED Spy's exploits was just to toy with him. Unfortunately, the BLU Soldier intervened at the last second, just before he was ousted.
 * Taking this further: the Soldier was the RED Spy all along. He knew that the BLU Spy knew who he was, and was planning to reveal this information after finishing his speech, but shot said Spy immediately before he could. (This also explains why the BLU Spy died instantly - the RED Spy used the Ambassador.) When it became evident that the BLU Spy was not a traitor, he tried to send the Heavy on a wild goose chase to find the "real" RED spy, so that he could slip away with the Intelligence. However, the Scout had figured out that the Soldier was a spy by seeing the difficulty with which the Soldier had figured out the password to the intelligence room, and tried to sneak up on him. Thus, the RED Spy was forced to drop his disguise, kill the Scout - as well as the Heavy, who was now a witness - and depart with the Intelligence and the pictures of Scout's mom.
 * Then how were the Soldier and the Red Spy seen together?
 * Simple: there was another RED Spy, this one cloaked, in the room at the time. He knew that his buddy had infiltrated the intelligence room disguised as a BLU, but he didn't know which class. When he saw the Scout sneaking up on the other two, he made the same conclusion that the viewers did, decloaked, backstabbed the Heavy, and was about to do the same to the not!Soldier. At this point, however, the Scout (who never considered the fact that there might be multiple RED Spies) decided that he had been wrong in his appraisal of the soldier, and unleashed an almighty batting on the second RED Spy. The first RED Spy, the one disguised as a Soldier, displayed absolutely no gratitude and promptly backstabbed the Scout, leaving with the Intelligence.
 * No, you see the Heavy was yet another RED Spy. Everyone in the room at the time was, in fact, a RED Spy, and there were several RED Spies Cloak and Daggered throughout the room. The montage of RED Spy backstabs was actually showing the enemies that each of the spies took out on their way to the Intelligence Room (with several left out for time reasons). The only individual who was not actually a RED Spy was the BLU Spy. He never got to finish his last statement. He was going to say, "It could even be all of you," but the Soldier Spy intervened too quickly.

In Meet the Spy, the BLU Spy had the Dead Ringer.
Shortly after the video ends, he decloaks and there's an epic fight between the two Spies; it was cut from the final video because the budget ran out.
 * It would explain how he instantly gets killed by a Shotgun.

But what if the Dead Ringer hadn't existed at all? The BLU Spy would be afflicted with...
The Curse. If you touch anything, you'd die. And the BLU spy was hit by shotgun fire to the head, therefore, among the many EXAGGERATED ways a character can die (getting so fatally numb from touching anything that you gain a literal black line across your eyes, incineration from a small laser bolt when it should cause a small burn, getting FROZEN TODAY from a snowball when it should just feel cold at the impact point, getting electrocuted from small un-bubbled electricity when it should be a tingle) it'd obviously quickly cause Your Head Asplode, as if his body wouldn't poof away into magic dust, which does not happen in the TF2 world explode anyway. This would of course deny the possibility that any one of us would see his eyes getting crossed off by a literal black line. Squicky and potentially disgusting detail:

The RED Spy didn't kill the BLU Scout in Meet The Spy
He knocked him out and stuffed him in a closet. After all, it would make his relationship with BLU Scout's mother awkward, and he does have a genuine affection for her.
 * Unlikely; after killing the Engineer and walking into the "always keep this door closed" room, he fired another shot...
 * Which could have been fired at Demoman or Pyro.
 * Probably the Demo (no way he'd have done so well if one of those cloak-revealing bastards were present)
 * Consider this: Meet the Spy and Meet the Sniper happened together in the same 'episode'. The RED Sniper killed the BLU Scout offscreen, allowing the RED Spy to take his place.
 * Makes sense, except for one thing - if the BLU Soldier shot the BLU Spy, then how could the RED Sniper have backstabbed him?
 * Dead ringer. Both times.
 * This Troper thinks that the RED Spy didn't get a chance to kill the BLU Scout because the BLU Scout was busy on the front lines.
 * According to these comics, the BLU Scout was dead by the time the RED Spy chose to disguise as him. Whether or not he was killed by the RED Spy remains unknown.
 * He could just be unconscious...

In Meet the Spy, the BLU Scout wasn't always the RED Spy. The Scout was killed in the middle of the BLU Spy's monologue
This explains why was the Scout able to touch the briefcase, and the fact that he gets pissed when shown pictures of his mother. Kinda sounds like Shut UP, Hannibal.
 * So, you're saying that that's NOT what your reaction would be if someone showed you pictures they secretly took of you having sex?

The person seen in the photos in "Meet the Spy" wasn't actually the Scout's mother, but a disguised Spy
In the pictures, the RED Spy was actually the BLU Spy being a triple agent, only to find out that Scout's mother was a RED Spy, who then stabbed him with Eternal Reward, disguising himself as the BLU Spy. Then, "Gentlemen?" Cue titlecard of Meet the Spy.

It was obvious. He's the RED spy.

 * Watch, he'll turn red any second now.
 * Confirmed, see? Red! No, wait, that's blood...

Everyone was a Spy.
Soldier's gun used the Spy's Ambassador's sound effect.
 * From a meta point of view, that may have been a red herring.

Scout's mom is a triplet. Her sisters are Cate Archer and Flo from the Progressive commercials.
Cate looks like Scoutmama if she decided to become a spy herself, and Flo looks as if she's cosplaying Scoutmama. It's the hair.

Waiting For The Combine--'Team Fortress 2 is a sequel to TFC and a prequel to Half Life/Portal
Half Life takes place in modern day, in a top secret science/industrial facility in the middle of the desert. Team Fortress 2 takes place about 30 years prior to Half Life's release, and is about a bunch of guys building some sort of complex in the middle of the desert. All the killing suggests that the project is rather shady and ethically questionable (you know, like a top secret science facility). Any inconsistencies (like the art style) can be explained by the copious amount of drugs everyone was on back in the 60s. I know the Half-Life connection has been brought up before, but TFC is the link between the two. The page for the engineer update shows the TFC engie with a young boy (presumably TF2's engineer) trying on goggles. That establishes the link between TFC and TF2. Now, on the TFC map "Ravelin" there are computers with the Black Mesa logo on their screen, thus establishing the Half-Life connection. TFC's "Hunted" map also takes place during a section of the Half-Life 1 Single Player campaign. Plus, Aperture Science and Black Mesa stock symbols are seen during the Spy Update.
 *  Black Mesa is a subsidiary of RED, Aperture Science of BLU  Even more believable if you are one of those who plays with the Aperture vs Mesa texture replacements. It looks so right!
 * Think about this in Half-life: Opposing Force you have to disarm a nuclear warhead in Black Mesa, as far as what's known, Aperture Science made no weapons of war, let alone nukes.
 * The portals are derived from teleporter technology, the Administrator is GlaDOS somehow, and Pyro is Chell.

The game is an allegory for American politics.
Before the current party associations for red and blue, red was the color of the incumbent party (i.e., the defenders), and blue the color of the challengers (i.e., the attackers). King of the Hill / Capture Point / Territory Control is vying for voting districts, Capture the Flag is a race to see who can dig up dirt on the other guy first, Payload / Payload Race are ad campaigns dishing out said dirt, and Arena are the debates (I have a rocket launcher; your argument is invalid).
 * Similarly, the announcer can be seen as the media (You only pay attention to her if she's focused on you) and Mann Co, is a catch-all company who provides the parties with funds/supplies. With the events of the comics, you could go into a whole mindscrew about how corporations really run the world and are sleeping with the media.

TF2 is a psychological experiment
The announcer is the head scientist and is staging the fights to judge whether or not people question motives. She places them on teams in a simulated environment and has them complete menial and completely pointless tasks in order to gauge how they react. She will continue the experiment until they begin to question why they are doing this.

TF2 is a promotional game set inside the universe of Saxton Hale.
What better way to show how handy having a Dead Ringer is, how great Jarate is, and how wonderful being behatted then to give everyone a taste? The Update sites are just Saxton Hale's Mann Co. ads. We get to play Mr. Hale's game, but in the port from the Saxton360 to the PC, the fact that TF2 is fictional and Saxton Hale isn't got lost.

Team Fortress 2 is the virtual viewpoint of cyborg soldiers.
Think Shadowrun: IRL. The electronic eyes/goggles used by the fighters have one image for each class, and each class posesses its own RFID code. The Spy classes have the ability to mask their RFID with a rotating-change section of the code telling its own team "I'm your spy! I'm masked!" and the other team "I'm a ____ on your team!" The individuals in the Meet The ____ are simply one person, either the best example of the class, or they are all on the current lead team for RED (or, most likely, both), which is why they look pretty much the same outside of "battle" (be it their "actual" face, or that they keep their "actual" "face" on outside of battle). The dozens of Soldiers and Demomen are just grunts in the same class, and aren't actually identical, and this is why the RED Demoman and the BLU Soldier being friends represent such a risk to The Announcer's plans and couldn't just be terminated.

The game is actually an incredibly dark examination of mankind's obsession with war
We've got a mysterious psycho obsessed with burning the whole damn world, A veteran who can never leave the war behind, a young man who greatly enjoys bashing people's heads in, and many others equally hungry for violence. And there's also a tiny little machine that provides literally endless health and supplies. There is no reason for this war to exist. Everybody on Earth could easily be provided for, yet the machine is only used for war. Hell, Sandviches heal just like Dispensers, suggesting that, inversely, Dispensers probably cure hunger. And yet, the war rages on, turning a machine that could literally solve all the world's problems into an ammo dispenser. Humans Are the Real Monsters, indeed.
 * The world's problems HAVE been solved. With no need for materials (dispenser), food (neverending sandvich), death (respawn) and injury (medigun, dispenser, sandvich) there's nothing to do but to fight over the one limited resource: pictures of Scout's Mom.
 * (Punchline: fantastic.) The battles are a sham, and deliberately limited to arena-like areas. Though the world is peaceful and prosperous, there's still people who want to fight or destroy. The "missions" are a release valve for society, and keep a army of fighters active and occupied in case they're needed.

A World of Darkness
The characters are all geniuses Not in the sense of being clever, but being one of the titular characters from the Genius: The Transgression New World of Darkness fan project (or perhaps a group of beholden equipped and controlled by an unmada or someone one the way there). Think about it; their weapons are either wonders, mainly made with Katastrofi (even the medic's medigun would need it for the beam effect), the medigun's powered by exelixi, the engie's sentry uses automata, the spies' cloaking device and disguise kit are from Metaptropi and the sniper's ability to generate jarate and the pyro and heavy's 1 hit kill taunts were down to a Progenitor modifying them. They're clearly all quite unstable. They're constantly fighting (for and grant money). The briefcase in CTF mode is a stack of blueprints. Furthermore all the bios imply events that could have lead to their catalysation;


 * Soldier: Grimm, from the anger of not being able to join the army. Or maybe Neid, from the need to prove himself as a soldier.
 * Sniper: Klagen, stemming from troubles with his family.
 * Demoman: Maybe Klagen from the remorse of blowing up his families, but since doesn't seem too broke up about it, perhaps Staunen, which lead him to tinker with explosives or Grimm from his feud with the Lock Ness Monster.
 * Pyro: Hoffnung, who knows what his real plan is but consider the fact that despite appearing to be an unstable pyromaniac he went out of his way to develop a flamethrower that won't harm his team-mates (even when friendly fire is turned on it won't ignite them) but will still incinerate spies. He clearly has some hidden depths...
 * Scout: Neid, from trying to keep up with his brothers both literally and figurativly. Consider his constant bragging about his prowess, and how much he taunts the heavy; he's jealous of his physique.
 * Heavy: Klagen, his guns are Replacement Goldfish for people he lost.
 * Spy: Hoffnung, his sneaking around must have a higher purpose and his rivalry with the pyro can be explained by their opposing agendas in changing the world.
 * Medic: Staunen, all he ever wanted to do was find out what makes the human body tick.
 * Engineer: Staunen, hence how he ended up getting all those Phds before he finally catalysed from sheer academical overload.

The game takes place in the same universe as Pixar's The Incredibles.
The visual, stylistic, and musical similarities between the two works are too great to be denied. So, the question is, why would there be two teams of nigh-identical warriors blowing each other to smithereens in this universe?
 * One possible explanation for this is that, following the re-emergence of supers, some shadowy multi-national conspiracy is assembling and training a clone army, just in case one or more supers ever needs to be put down—similar to the Cadmus project on Justice League Unlimited. The fact that these exercises are live-fire and clearly lethal suggests that battlefield experience and training is hard-wired into each clone, so that each one comes out of the vat a little bit smarter than his predecessors.
 * Another theory is that the two clone armies are killing each other for sport. They're duking it out, gladiator-style, for the entertainment of those rich and hedonistic enough to finance this sort of thing. "Red vs. Blue in a bloody, explosive duel to the death, this Sunday, Sunday, Sunday on Pay-Per-View!"
 * Or it could be a bit more logical and still take place in The Incredibles: two Arizona-based evil organizations sprung up in close proximity and spend all their resources pounding each other into the ground. Neither has the time, money, or desire to expand operations beyond hiring mercenaries to fight it out. Since the movie obviously takes place somewhere more temperate, the two never really deal with each other.
 * All the classes are Supers. If you think about it, each class can do something extraordinary. The Scout can jump in mid-air, the Pyro can shoot fire from his/her palms, the Soldier is a berserker with the Equalizer equipped, the Engineer can build death machines by smacking them with a wrench, the Heavy can heal ridiculously fast from two bites of a sandwich, the Demoman has depth perception despite having one eye, the Medic can make you invincible and has a healing factor, the Sniper's kidneys are probably half his body weight, and the Spy can turn invisible.
 * ‘’Alternate Universe: Pixar Watch Valve’’ Which could also extend to Watchmen: The Superhero Registration Act (SRA from now on) was more extreme for the part of America The Incredibles were in, forcing them to go into hiding and move, rather than the Minutemen's example of just suitting vigilanteism. There were no Supers where the Minutemen were, which, if true, could be the explanation of the G Man putting Freeman in a hyper-sleep for 7 years. Freeman attained "Super" status after Half Life 1, G Man hid him away and made the SRA go away, and bring Freeman back legally. Or rather, the Combine made the SRA go away and G Man brought Freeman back to stop them and stop the SRA. The Citadel that blew up at the end of Half Life 2 wasn't really from a core meltdown, it was from one of Ozymandias' bombs going off in that area and, since he kept it such a good secret, no one knew about it and went along with the core meltdown. While the RED missle in Dustbowl and Steel is one of Ozy's bombs, Blu is trying to stop it thanks to Jon's (represented by the Blue colour of course) insight that he pretended to lose. Team Fortress 2 takes place all over the place in terms of timelines; Before, after, during. And of course, Portal takes place at least before Monsters Inc, as they hired Arperture Science to make their door portal technology to get into childrens' rooms.

Team Fortress 2 is a Stealth Parody of online gaming.
Also notice that there are no female playable characters, a jab at the "no girls on the internet" joke. There is the obviously female announcer, but she's the one running the show; why should she kill people when she can make a dozen idiots do it for her?
 * The Scout: That micspammer/12-year-old boy with a headset and too much free time. Knows how to break the game in new and startling ways (such as the double-jump and the ability to dodge every kind of damage ever for about eight seconds). Incredibly embarrassing to be killed by (even more so when he kills you with the Holy Mackerel).
 * The Soldier: The Stop Having Fun Guy who treats Capture the Flag as Serious Business. Acts like the game is a real war. Only user of weaponry that could actually be found in military hands (everyone else's looks like they made it themselves). Most of his vocal lines sound like they come from Drill Sergeant Nasty.
 * The Pyro: the guy (or gal) who never talks and uses the weird weapons, but is somehow incredibly dangerous. An enigma: no one knows anything about him, but everyone runs in terror (or runs for health packs or the medic) when he comes through.
 * The Demoman: the grenade spammer, who still uses the same tactics that dominated the previous game. Also the guy that prefers blades to guns.
 * The Heavy: the guy who gets the BFG he can find and then mows everyone down with it. The guy who has little care for tactics beyond "Shoot It Until It Dies."
 * The Engineer: representative of the mod community. Builds things that augment the game and alter the course of battle.
 * The Medic: the most straightforward example: the player who does everything he can to be a team player and help other players survive. The guy who actually cares about winning.
 * The Sniper: the camper who sits back and shoots people from long distances, because if he gets in close he's screwed. That guy who only uses the gun with the incredibly long recharge rate but kills in a single hit.
 * The Spy: the team-killer. The stealthy evil asshole who uses the knife almost exclusively. That guy on your team you can't trust because you know he's going to eventually turn on you, even if it's just for the lulz...but you keep him around anyway because you need him.

The game is a prequel to Killer7
...somehow. Perhaps the team are early versions of Heaven's Smiles/the Personas, or some combination thereof.
 * The Heavy is MASK
 * Wouldn't that be the Demoman?
 * MASK is The Soldier
 * The Scout is Con
 * The Spy is Kevin
 * This troper prefers Dan as the Spy and Kevin as the Pyro.
 * The Spy is closer to Coyote than Dan.
 * The Sniper is KAEDE (somehow)
 * The Sniper is Harman is more accurate
 * The Medic is Garcian
 * The Medic is the guy that operates the Blood Machine

TF2 is the American Equivalent of the Reaper's Game
All the characters previously died, and are fighting for their one chance to come back to life. They must survive until the end of the round, and must complete whatever mission they are given, and are forced into one of 9 forms to make sure they are fit for battle. All the classes are Players, the Administrator is the Composer and Saxton Hale is the Producer. This version of the Reaper's Game, although shorter than the one in Japan, generally contains a much higher casualty rate.

The characters are avatars of the various gods from Warhammer 40k

 * Scout: Gork/Mork (the smart one)
 * Soldier: Khorne
 * Pyro: Malal
 * Heavy: Gork/Mork (the violent one)
 * Demoman: Slaanesh
 * Engineer: The Emperor
 * Medic: Nurgle
 * Sniper: Khaine
 * Spy: Tzeench
 * Helen and Saxton Hale may be C'tan
 * Objection! The Engineer is clearly the Void Dragon, the C'tan Machine God. The Announcer is the C´tan Deceiver. While Saxton Hale´s overall combat ability, hatred of hedonistic hippies, supplying of weapons and shining leadership by example clearly mark him as being the God-Emperor of Mankind. (Besides, whose name would you rather call out as you visit His wrath upon your enemies? Dell Conagher, or SAXTON HALE?)

The game takes place in the same universe as X-Men

 * All the classes are mutants, as they can all do extraordinary things (see above Incredibles guess) This would also explain the two Pyros. The time periods would fit as well, if we look at the earliest publication dates of the X-Men- possibly Mutants are just beginning to emerge from the woodwork.

Global Agenda takes place in the Team Fortress 2 universe.
In the far future, the coorporations gave up on fighting over land and came to realise they could make far more money by selling their geneticly engineered soldiers to the goverment. Then they realised this wasn't very fun, and began to hire freed agents of their own design to fight over worthless landmasses. They originaly spliced together the Sniper/Spy/Scout, the Heavy/Soldier, the Medic/Pyro and the Engineer/Demoman.

The Sims 2 is related to Team Fortress 2 in some way.
The Engineer can build killing, healing, and teleporting machines, and upgrade them, by hitting them with a wrench or punching them with a bionic hand. Sims can build sentient robots by bashing a piece of metal with a wrench and screwdriver.

TF2 is set in the past of the Sam and Max universe
In season 3 Episode 4 of the Telltale games, there's a BLU dispenser located in the tunnels under NYC. The Sam and Max items made available to players for preordering the season wound up in the past due to one of the Freelance Police's many time travel adventures. The art styles are pretty close, too.
 * But how would that mesh with Abraham Lincoln being an alien spy as in the Sam & Max games?
 * Perfectly.

Obviously, this takes place in the Fate/stay night universe.
I'm ashamed I haven't thought of that earlier; we have people only named after their Classes (Medic, Spy, Sniper, etc.), we have them fighting for the Intelligence (the Grail) and territorial control is obviously used to get a sacred ground to summon the Grail.

Team Fortress 2 takes place in the same universe an Command & Conquer: Red Alert
RED and BLU are secretly controlled by the Soviets and Allies respectively. Word of God states that The Medic was never a Nazi. That's because, in this world, the Nazis never came to power (but they still existed, enabling The Soldier to kill them) explaining The Heavy's willingness to work with The Medic. Also, Spies. In both universes they have the ability to disguise themselves as an enemy unit though some kind of holographic technology. (Not sure where the Empire of the Rising Sun fits in...)
 * This video will explain a lot. The Empire of the Rising Sun will be the new Orange Team.

Every one of the characters in the game is already dead.
No, they're not in Hell, or Purgatory either. Instead, they've been taken by the valkyries to Valhalla, where they spend their days in constant, glorious combat, preparing for Ragnarok. This is why they're able to "respawn" after being killed; since they're already dead, they're effectively immortal. Even better, each of the team is from a different time period, it's just that this Valhalla updates itself to the newest arrival, and he showed up in the 60s. Here's an interesting time frame for when the characters showed up. Heavy: 1940s, perished in WWII Medic: Early 1900s, Mad scientist from the steampunk era, died after he went insane and attacked the town. Soldier: 1960s, the most recent arrival, he used to fire on hippie protesters. He never expected one of them to fire back Scout: 1920s, was a rumrunner for a bootleg gang (alongside his ma, who was dating the boss) killed in police shootout. Demoman: Dark ages. He and his parents were sent to Scotland from the exotic land of Egypt to teach the king how to use explosives. Pyro: thrown from the TARDIS in an unidentifiable place in the time stream. Spy: French Revolution. A bastard son of the king, he used his wits and cunning to keep his head... until that barfight at least. Engineer: 1850s, Railroads were just cutting through Texas and he made sure they kept on time. Sniper: A former member of Ned Kelly's gang. Maybe even Ned Kelly himself!
 * If Armageddon turns out to be a game of Capture The Flag, I'm leaving.
 * And going where?
 * An afterlife with a team deathmatch server or two.
 * With the new Arena mode, that's now possible.
 * Everyone knows only true warriors play Territorial Control anyway.
 * The Heavy hides this one in plain sight—one of his voice taunts is "All of you are dead!"
 * He was talking about the people he killed, not the ones which are still alive.

The game is in the same world as Red vs. Blue.
C'mon, the endless, pointless fighting, the oh so cheap death and rebirth, the fairly unhinged troops, the unyielding alliance to the color for no good reason... This is just another front in the blood gulch conflicts.
 * Not to mention that the voice on both sides' PAs sound identical.
 * Grandpa Conager's machines still work?! That man was clearly the most brilliant genius who has ever lived. Shame he never used on on himself.

The game takes place in the Fallout universe
Specifically, the game is a stage-play put on somewhere that was turned into a Utopia by a GECK about warring tribes that survived the holocaust with some semblance of resources. This is why the art direction, by Valve's admission, leans toward making everything look semi-homemade; they had to make do with what they had after the nuclear fire wiped out the infrastructure. The battle appears pointless and fought between clones because the play is highly fictionalized. The equipment is to be taken literally, however, because things like the Medigun and the Spy's gear would fit right in with Fallout's zany retro-futuristic technology.
 * Possibly, the stage-play is like those that happen in Paper Mario: The Thousand-Year Door; namely, that the staged fights are real, just on a stage.
 * Also, the Pyro is a ghoul who wanted in on the play, and was made to wear the gas mask and suit so as not to freak out the other actors.
 * Theoretically, it could also be like the tranquility lane simulation, reset every time somebody dies/every match.

All of the battles are actually a televised sport, like Unreal Tournament.
It’s a very, VERY sick wargame. The family fued backstory is true, but some descendent must've thought to himself, "If this was a result of Zepenniah wanting his sons to fight over something so he could watch, why not have EVERYONE watch it?" It's top secret so no government could come in and arrest the companies. The truth will come out to the classes when they unmask the Pyro and reveal thats it's a four-year-old girl with no idea what death even is yet. Both teams will team up and capture the Announcer and Saxton Hale, bring them to the FBI (or something else) and have them arrested.
 * Confirmed to an extent; when Doublecross was released it was mentioned the people who live around the Badlands where the teams fight sometimes watch them and aren't fooled at all.

The game takes place inside The Matrix.
Everytime a character is killed, they almost immediately respawn, and don't consider how they survived explosions/headshots/etc. The Matrix repairs their body and makes them forget what happened in their "past life" before the mind decides to let the real body die, and all they know is that they have to fight the other team for the MacGuffin. The One will emerge when they realize that touching a medicine cabinet instantly heals all their wounds.

The game takes place in the Looney Tunes universe.
This makes EVERYTHING, and I mean EVERYTHING, make sense. (also, requesting Looney Tunes TF2 cosplay fanart)
 * Ehhhh, what's up Medic?
 * Oooh, dat skwooy wabbit's sappin' my sentwy!
 * This would make Sniper's "What's up, Doc?" domination line hilarious.

Team Fortress 2 takes place in a Higurashi no Naku Koro ni style Groundhog Day Loop.
It seems as if it's always June 1968. And those who are killed are always resurrected.

This game takes place in the same universe as Super Smash Bros.
Capture the flag, Soldier only, no items! Somewhat suggested by this.

The game takes place in the Metal Gear universe.
After the success of the Cobra Unit during World War II, there was interest in creating more multinational combat teams of eccentric, homicidal Bunny Ears Lawyer supersoldiers. Both RED and BLU are secretly controlled by the Philosophers. And Peter Stillman in MGS 2 probably has some connection to the Demoman.

The members of the Teams don't die, they get desynchronised.
The Announcer is a Templar and the games are staged to distract the viewers from the Crapsack World outside. As to how they found people descended from the Team Members... best not ask that question.
 * Why not?

Team Fortress 2 takes place in the same universe as 1984.
After the nuclear wars of the '50s, Oceania and Eurasia began to establish themselves as megastates, but this theory speculates that the 24/7 surveillance of everyone everywhere, brainwashing and revision of history took longer to establish. So while Oceania and Eurasia began waging their perpetual wars to consume resources, they also decided they could use these wars to kill (or at least keep away from the general population) a few axe crazies with....unique, personalities, and strong senses of national identity (even though their countries no longer exist). The battles keep the mercenaries away from the impressionable civilians likely undergoing preliminary conditioning, and use up resources (which is the whole point of the war). $400,000 for 12 seconds of minigun fire sounds like a good investment to me. Oceania is BLU, Eurasia is RED, and Eastasia was formed after the other two, and was not organized enough to contend in the battles covered by the game. And obviously, the Administrator is behind the whole thing with  as a lieutenant and trusted advisor.

Each class is designed as a counterpart to different races and/or factions of Warhammer 40,000

 * The Scout is the Eldar. He is very fast, physically frail, and does hes best damage at close range, but isn't too bad at medium range, either. Note that it is very dangerous for a Scout to stay in one place for too long, in a metaphorical parallel to the Eldar's constant fleeing from Slaanesh.
 * The Soldier is a Space Marine. He fill in the role of the well balanced fighter, his primary weapon fires RPGs (though, being in Warhammer 40k's ancient past, it's much more primitive than a Bolter), and he also has the crazy Blood Knight attitude. His weapons show a distinct lack of chainsaws, but if there's any weapon in TF2 that would fit in Warhammer 40k, it's a pick-axe that does more damage the more injured it's user is.
 * The Pyro is Chaos. This makes quite a bit of sense, given his ambiguous gender (like a certain Memetic Molester), fire based and brutal weaponry (matching the hellish tone of the Warp), and his general terrifyingness.
 * The Demo is... a Chaos Space Marine, I guess. Like the Soldier, he has powerful weaponry, but thanks to his sword, is also adept at close range. Said sword is also haunted, and fills him with rage and a thirst for destruction.
 * The Heavy is the Ork. Nuff said.
 * The Engineer is the Adeptus Mechanicus. Technologically oriented, and does his best work outside of direct combat. He doesn't worship machines but, just as the Adeptus Mechanicus's prayers have a weird tendency to work, his Percussive Maintenance has an improbable success rate. He didn't always fit well, but recently, he's started using technology designed way before his time, and even replacing his limbs with machinery.
 * The Medic... Necron/ The Mad Dok.
 * The Sniper is the Tau. Sucks at close range, nigh unbeatable at long range. Like the Tau, he's the easiest to imagine as a good guy, as he hasn't shown any overt insanity, and is hardly even a Cold Sniper. His height is played with, as he is the second-tallest class, while the Tau are short.
 * The Spy is the Dark Eldar. His Memetic Molester status more than qualifies him. He is also constantly hunted by the Pyro, who, as previously mentioned, is Chaos.
 * Alternatively, they're all orks

Fortress Team Hetalia: The game is a geopolitical allegory.
Obviously, each character represents their national stereotype. However, it goes far deeper than that:
 * Medic/Germany and his relatively good interactions with the rest of his team as a healer represent the importance of the German manufacturing industry to all economies of the world, whereas the tendency for the other team to Shoot the Medic First is obviously a reference to Germany's role in the world wars.
 * Medic/Germany-Heavy/USSR relationship represents the relatively good relations between Germany and Russia/USSR until the Second World War (which is justified by the Heavy being a significant threat to medics on the opposing team)
 * Spy/France reflects the historical stereotype of backstabbing French (eg. Spy-Heavy conflict reflects WWI/WWII, Spy-Medic the long history of Franco-German warfare) and general negative perceptions of the French by the Anglo-Saxon world.
 * Soldier/USA is the 'jack of all trades', which represents the USA's tendency towards realpolitik and highly variable relations towards the Old World powers.
 * Pyro (faceless) represents grassroots independence movements and guerilla groups throughout the world, leading to his antagonism to imperialist powers (Scout/USA, Heavy/USSR, Spy/France, Medic/Germany).
 * Engineer/USA represents American international development aid (NEED A DISPENSER HERE!).
 * Engineer's antagonism with Spy reflects mid-20th century criticism of French imperialism by the US.
 * Engineer's friendship with Pyro reflects American aid to independence movements.
 * Sniper does not represent Australia so much as British colonial interests, which makes sense given Sniper-Spy (conflicting French and British spheres of influence), Sniper-Pyro (imperialists vs. independence movements) and Sniper-Heavy (eg. Great Game, British suppression of communist independence movements in its colonies) antagonism.
 * Scout/USA represents the chaotic viewpoints of the American public, and is sometimes helpful but generally just pisses everyone else off.
 * Scout is a natural enemy of Heavy, which makes sense given the Cold War and Russia's resurgence under Putin.
 * Scout-Engineer relationship represents conflicting attitudes of the American public to foreign aid; sometimes negative (Bonk energy drink) and sometimes positive (NEED A DISPENSER HERE!).
 * Demoman ('Ah'm a black, Scottish cyclops!') represents the Third World, particularly African and Middle Eastern immigration to the West; a good Demoman is an asset to the team, but is nevertheless hated by everybody else for mostly invalid reasons. Demoman-Engineer antagonism represents the War on Terror.

Medieval mode takes place in...
Soldier didn't just insult a magician, he insulted the one known as "Zero".
 * Thanks for the idea... To the Fanfic-Mobile!

The game takes place in the same universe as The Venture Brothers.
I'm not sure I really need to justify this one.

TF2 takes place in the same universe and around the same time as Moon
The same company that provides fuel from the moon is also conducting military reaserch and development, utilizing the same cloning technology in both ventures.

The characters are actually holographic projections to cover floating heads with arms
Notice how, while other characters appear to be fully formed humans, your own character can look straight down and not see any legs, feet or body. This explains how characters can rocket jump without blowing their feet off, the floating head is simply blown up by the explosion some feet beneath. Why this occurs is something for another WMG.

The game takes place in the same universe as Punch-Out!!
Think about it: they both have the cartoony style despite the violence, and the characters have the most common stereotypes of their nationality.

The whole world is a simulation run by Aperture Science
GLaDOS, or a backup or her at another site, is Helen and she manipulates everything. Another Adventure Core is Saxton Hale.

Again, it's the world of Half-Life/Portal, but not the past. TF2 is in the future.
While Chell was in stasis, Gordon Freeman and company crowbarred the Combine off the planet. With everything wrecked, first by the invaders and then by the war against them, civilisation had to be rebuilt, resulting in TF2's Schizo-Tech. Strange effects from the invasion also manifested in Australia, creating Australium. Portal 2 is concurrent with TF2; Chell will emerge to find things at a sort-of '50's-'60 level, hopefully encountering RED first. (Orange being closer to red than blue.) If she tells them about the Enrichment Center, RED and BLU will soon be fighting to posess it.
 * And Wheately is going to get knocked down from space around the same time, get picked up by BLU (for obvious reasons) and lead them to Aperture.

Team Fortress 2 and Fallout take place in the same universe
The Fallout universe's timeline split with our own after World War II. They sacrificed cultural development, but are much more technologically advanced than our universe. In TF2, which is set in 1968, there are machines that give out infinite health and ammunition, magical backpacks that do the same, robot hands, and I don't even know what else. Nuclear power and energy weapons have yet to become widely used, and everything else meshes pretty well.
 * Actually, Fallout's universe isn't all that much more advanced than ours... as far as we know yet, at least. Remember, not only is the technological level of Fallout in some ways behind ours, but the technological level showcased in Fallout dates to 2077. We still have six decades to develop all sorts of fun stuff Fallout doesn't have. Basically, as far as Fallout tells us, there shouldn't be machines that give out infinite health and ammunition in 1968.

The actual corporate headquarters of RED is on the pl_Cranetop map
It's the stage three base of the Red team. That location is exactly the sort of headquarters location that would fit a super powerful corporation in a game based around 60's spy movies. The location of the Blue corporate headquarters is still unknown. (For those who don't know what cranetop is: http://wiki.teamfortress.com/wiki/Cranetop )

The payload game mode is a Uriah Gambit in Blue's part to get rid of mercenaries
Blue has succeeded in doing whatever it was trying to do on the attack/defend maps, and now wants to get rid of its mercenaries to prevent them leaking secrets, working for other people, or just being some sort of threat. So, naturally, they send the mercenaries on a partial suicide mission against some RED target. This is why the bomb explodes immediately when it reaches the end, killing nearby blue characters, and why more payload missions have been released as time goes on. Of course, given the respawning nature of these mercenaries, it is a difficult plan ot pull off...

The fight is still going... as TF2

 * Everything in what we think of as the TF2 Universe is actually real, except for the fights. Originally, the fights were ALL like Arena mode, as there were no respawns - you were dead. Increasing costs of repeatedly getting new mercenaries, and the advent of online gaming allowed TF industries to create what we treat as just a game, but is infact the same battles as were previously being fought by real people.
 * Valve was created specifically for the release of TF2. The original mod had unwittingly stumbled upon thier mode of fight, so they bought the rights for it so they could make what was released as TF2. The previous games (Half Life, Counter-Strike etc) were created to establish a fanbase and a name for themselves, to ensure a huge volume of people would buy it, allowing for the maximum number of disputes to be solved.
 * The characters are modelled on the greatest examples of the mercenaries that used to fight, including their actual backstories. That's why they all die so easily - not because they're just imitations of the real thing, but because the best are being pitted against the best, something that almost never actually happened.
 * To hide their existance, RED and BLU collaborated to create the history we're taught. Due to fans wanting more depth to the characters, they started to release details of the real history (to ensure nobody started trying find out on their own), and recordings of the characters the game was based around - the Meet The Team videos (with modern software creating the "cartoony" style to help hide the actual identities).
 * The videos create the apparent gamplay/story segregation because they were facing regular mercenaries, who simply were nowhere near as good as them, though in the game, they're facing other pros, so naturally don't seem as good. The fights are actually incredibly impressive, but as they're what we're used to, they just seem normal.
 * Australia WAS the leader in technology, but have since used up all the Australium. As it's been redistributed around the rest of the world, the global IQ has increased, allowing other countries to create just as, and even more, advanced technology.
 * The reason why "Valve" are so ambiguous about the Pyro's gender? They never actually knew it. Most of the Hired mercenaries that were similar had things like fitted suits, or didn't wear masks, and due to weaknesses that allowed their genders to be percieved, got killed. The Pyro was the best of the best because s/he had a suit with almost no weaknesses, and was constantly wary, so never removed it. The reason for his wariness is counterintelligence training, which is why s/he is so good at finding spies, as well as arriving unannounced to ambush defenses from behind. The suit makes it impossible to be as good as the spy, but s/he can still hold hir own.
 * All the revealed backstories are not only true, but partly reveal how they became the best:
 * Engies grandfather built the lifemachines, but came before the war truly started, so his grandson, who was eventually hired, had all his plans, and modifications of his own to add and make them even better.
 * The RED spy was sleeping with a scouts mother (maybe even one of the Scouts brothers), and was so good he even managed to get her to keep the secret, until the BLU spy (his just as brilliant twin) discovered it. He murdered the heavy and soldier so brutally (he only really needed to stab them once each, but there's a lot more than that) because, despite being rivals, they were still brothers, and he was enraged by his death.
 * The Soldier and Demoman actually met, and their friendship arose from their equal skills - while others were dying left right and centre, they regularly met on the battlefield, and struck up a friendship as a result.
 * The Heavy and Medic also met, but before the war started - specfically, in the Gulag the Heavy broke out of:
 * The Medic WASN'T a Nazi, but joined the war as a field medic, as he wanted to save as many lives as he could. After being captured by the russians, and sent to the Gulag, he eventually went crazy as a result of seeing the horrors of war and the gulags. The reason why all the soldiers in the Gulag were tortured to death was due to the crazed medic - he was so enraged by the atrocities that had been commited, he wanted all of them to pay.
 * Eventually the friend he met in the Gulag, the Heavy, calmed him down as they escaped, forming an unbreakable friendship. As the Heavy grew up in the war, he had grown used to the guns only stopping when shelling was about to start, so became terrified of a lack of bullets flying, and forming his attachement to guns, especially ones that fired lots of bullets.
 * The Scout, as a result of growing up with so many brothers, needed to be quick AND decent in a fight. Some of his brothers were so much older than him that the only way to not get beaten up was to be able to run away, and the ones only slightly older than him had had the same experience, so he needed to be able to hold his own. If you grew up where he grew up, you WOULD be dead, as you weren't trained from when you were young to fight (or flee) for survival. His mum was kind of a slut (and one or more of his brothers may be courtesy of the Spy (possibly even the Scout), explaining why he never met the Spy; the Spy had passed on/retired by the time Scout joined the fight), which is why there's so much fighting between the siblings - they all have different fathers, and want to prove that theirs is the best.

The game takes place within the Inception World.

 * In inception, the dream sharing technology was originally created for military training purposes. The Team Fortress 2 world was created when someone used a sedative that was too powerful to allow waking up on death, accidentally bringing the soldiers into limbo during the exercise. While in limbo, the dreamers continued trying to train, becoming the mercenaries, while the overall person supervising the training (whatever they'd be called) continued to try and supervise. However, thanks to not remembering where they came from or who exactly they were, the soldiers turned into mercenaries, probably representing more suppressed aspects of their personality, while the training supervisor became the announcer, and mentally built several arenas for the soldiers to fight in. The soldiers would have fought for several decades, continually respawning because in limbo there is nowhere else to go to after dying, until the sedative ended and they woke up, the first people exposed to limbo, and a source of information for how limbo works.

The world of Team Fortress 2 represents the balance of life being upset
Seeing as we have a conflict between Builders League United (creators) and Reliable Excavation Demolition (destroyers), there seems to be some sort of Yin Yang relationship going on between the two teams; when one defeats the other, the aspects of life get thrown off balance.

The respawn system is set with The Flesh.
A constant cycle of lives with no consequence of death? Given the amount of Australium powered reality bending devices we've already seen from the canon, it's possible that 'the government's worst kept secret' would be among them.
 * That respawn countdown? It's the time it takes to whip up another Ganger and drop it into the map.
 * It would also explain why the two teams are exactly alike. The Administrator could have set each character to have two Gangers, one on each side to fight themselves forever.

The teams are composed entirely of Butlers.
Blutarch hired them and Redmond cloned them instead of hiring other mercenaries because it's hard to outdo a team of nine Butlers.

Ribs don't grow back.
Heavy had a spare.

The Demoman's eye really did grow back.
But since he never takes off his eye patch, he couldn't tell the difference.

Archimedes is the reason why the Scout double-jumps
And in general, Archimedes would aid in the aerial mobility of the Scout after being accidentally shut inside his chest cavity. To add to this, an Atomizer Scout can triple-jump but take a bit of damage, which to this WMG would mean that Archimedes would push hard against the Scout's chest.

Archimedes is immortal.
Well, it's that or the pigeons are all Archimedes, one at a time. Considering the Medic, either is possible.

The Medigun can stay Ubered for as long as the Medic wants.
It just breaks if he uses it for too long, which explains the 12 second Uber in Meet the Medic, so the Quick-Fix can't invuln, and the regular Medigun can only Uber for 8 seconds because the Medic doesn't want to risk breaking it again.

The Medic really does care about healing, and it's not (as his bio states) a wholly unintended side effect.
Healing means he can do more things to a given patient before they die. He actually devotes energy toward finding devices that can heal (such as the Medigun, and the Medigun Prototype that was in his lab as of Meet The Medic). If his patients die on the operating table, he can't leeeeaaarrrn as much from them that he couldn't learn from slightly less fresh cadavers. Therefore, he lied about healing only being unintended side effects; they're a means to an end, but at the very least, his earlier results of healing mechanisms were fully intentional.
 * He cares about his patients not dying. Healing is an unintended side effect of that. It does sound crazy, but he is a mad doctor after all.

The Scout has an antelope or gazelle heart in him.
It makes him speedy, and doesn't have all the blockage and rads/caffeine that years of unhealthy beverages and cheap food have given him. If the Heavy's heart exploded, how could the Scout's heart withstand the "upgrade"?
 * And I think he got the Loch Ness Hamster one.

Heavy's heart exploded because it was full of plaque and cholesterol.
Many sandvich no good for heart health. Vodka, better, but maaaaybe not good for a strong physical heart. Scout's heart is totally fine because of all the cardio he does, and the fact that his cola has totally mutated him into a super-cool rabbit-heart-mutant thing- Erm. Because of all the cardio he does.

Medic has no idea what gender Pyro is
Despite cutting open his/her chest. By that point in the day, his glasses were so covered in blood he was trying to shove the heart somewhere around Pyro's eye socket.
 * That or he cut open Pyro's suit instead of having him/her taking it off and just let the healing ray fix the Clothing Damage, as he did with Heavy.

Medic doesn't get an awful lot of sleep.
He has rather obvious dark circles around his eyes in "Meet the Medic". None of the other classes look like that, so it must be significant. Do you know what keeps him up at night? After hearing people whining for him to come heal them all day, he hallucinates that he can still hear them at night. So think about that before the next time you spam E because it amuses you, or you like your class's voice, or it's a tic, or you've forgotten that the Medic does not hand out ammo, or...

The Medic is an ex- Depraved Dentist.
He got into it because he enjoyed hurting people. Then he found out that being a mercenary doctor lets you hurt people even more.

Medic both lacks 'any sort of verifiable formal training in medicine' and had his medical licence revoked.
He fled Medical School for some reason and had a fake Medical licence made so he could go into practice, which he lost when...

Pyro supplies Medic with the bases for the mediguns
They look like modified firehoze nozzles. Maybe Pyro picks them up for him when s/he goes out to troll the Teufort fire department.

On the respawning system...
Instead of all the cloning B.S. and such, 'respawning' in TF2 means you are just patched up by an off-field medic, explaining the 20-second wait. switching classes means that you call in the nearest-by heavy, medic, pyro or what have you, and it still takes 20 seconds. I mean, this is a game where ghostbuster-styled guns can close up any wound, you can turn invincible for 8 seconds, and fight off floating eyeballs with a laser gun.

Gordon Freeman exists in the TF2 universe...
...but since Australia holds a monopoly on the world's technological development, he's a grizzled old airboat captain who offers tourists rides. There's a sign saying "Freeman Airboat Tours" on the Mountain Lab and Lakeside maps. Clearly many people come from near and far to see the classes blow each other up.

Medieval Mode isn't actually set in medieval times
The map is just an amusement park that the teams stumbled upon. Being largely a a collection of lunatics, they merely assume that they're in the middle ages, and think that using guns will cause some sort of present-day-altering butterfly effect.
 * Y'know, my brother played Medieval Mode and found a computer. Or whatever that thing is. Y'know, one of those computer-things that are everywhere in 2Fort. If you want to see it yourself, it's behind a half open door in the RED spawn.
 * Alternatively, the Soldier didn't piss off a magician, but a hypnotist. The latter stole everyone's guns, made the teams believe they had time-traveled, and laughed all the way to the bank.
 * To support the amusement park idea: Around DeGroot Keep, there are a total of three computer terminals visible, there's a portrait of the Demoman's family, the signs are in modern English, there are sirens and control points and modern-day ammo pickups, and there's even a ticket booth model in the game's files, all suggesting the teams are in some medieval simulation.

The Engineer can play any song on a single string of his guitar, like this.
And on that note:

Every G Mod video and YTPMV actually happened in-universe.
Maybe they have too much free time. Maybe I have too much free time.

The battles are entertainment in-universe
Of the gladiatorial variety. The whole "two corporations secretly ruling the world" thing is just a storyline cooked up by the fight organizers. Seriously, it's pretty hard to keep a pitched gunfight secret, not to mention the mercenaries themselves—no sensible person would hire people that crazy.
 * Well, a number of the maps are in far-off, abandoned locations, and the official description for one actually mentions people going out to watch the teams fight. As for the mercenaries themselves... well, do the brothers Mann really seem like sensible people to you?

The game shares a universe with The Adventures of Dr. McNinja
Inspired by these links. It certainly would explain the Fantasy Kitchen Sink being gradually added to the gameplay.

Doc Brown is responsible for the Anachronism Stew in TF2.
Poker Night At the Inventory features a cameo by Trixie Trotter from Telltale's BTTF game, thus confirming that (at least in the Inventory continuity) it's in the same universe as TF2. Doc Brown became friends with Engineer and Medic, and brought them back trinkets they'd possibly find useful, like iPods.

During spectator mode, you are playing the Announcer.
Or, since you can't issue orders, you could be playing Miss Pauling.

The Christmas cards are canon
Every Christmas(Smissmas?) the teams, perhaps coerced by their Engineers, call a truce between RED and BLU for the day and celebrate it together. The Administrator doesn't know about this which is why it keeps on happening, though it usually doesn't last more than half a day before they start trying to kill each other again. This guess incidentally means Sniper actually knows how to knit jumpers.

Merasmus was originally intended to be a hired mercenary, but the Soldier decided to be spiteful.
With the possible exception of the Pyro (and Heavy, if you consider his degree in Russian Lit. to be non-canon), the rest of the team has incredible potential outside of their mercenary work; and in some cases, hired because of this potential. In fact, historical evidence shows that this isn’t just a coincidence; prior teams have been composed of historical greats, as well. In this 'League of Extraordinary Gentlemen'-esque setup, where does Soldier, a lunatic who decided to go on a Nazi-killing rampage several years after World War Two ended, fit? The short answer, he doesn’t.

Around the time the nine mercenaries were first being recruited, Soldier somehow caught wind that Merasmus was to be hired as a mercenary instead of him. Obviously quite frustrated with these circumstances, the Soldier then decides to commit the most glorious act of identity theft of the 1960’s, effectively being recruited for hire in place of his roommate. By the time the mistake was noticed, it was far too late to rectify this mistake, and so the Soldier stayed.

Incidentally, this would also explain the incident that first pissed off Merasmus. Upon finding out that Soldier stole what can only be described as a 'very' good employment opportunity, he retaliates by sending Soldier and the rest of the team to the 14th century.

The pictures and numbers in Foundry will develop with updates

 * Over the course of the next couple updates, the photos will slowly be changed to more and more developed versions of the same picture, eventually showing what they are just as the update comes out.

The Foundry map holds the key to the identity of The Pyro.
The Pyro is not a he, or a she. Pyro is a robot, created by Engineer; (some of his eleven PH Ds could be in biological or robotic engineering), possibly as a prototype for the Manns, as transferring their brains into robot bodies would be an easy way to appease them while Dell could keep the life extender machine's blueprints for himself. The suit actually IS the Pyro's skin, and beneath the eyes of the gas mask are cameras, possibly in infrared. More evidence for this theory can be found in Meet The Spy: (One of the possible messages on the alert screen is The Pyro is/a Robot,) True Meaning, (Dell lives with Pyro) and The Foundry map: There are photos in the RED team's room on Foundry, and a prominent bloodstain in BLUs. 1961 is the year the Unimate robot was first installed on an assembly line, while the neatly divided sectioned word fragments in the sign reading AUTO-BORAX spell "ROBOT" backwards. While we're on the subject, guess who uses the ax? As for when Meet the Pyro comes out... maybe AUGUST of 2012? Alternatively, an Australium Ax could be the Pyro's next weapon...
 * In the Engineer update video, you can see two robot heads in the background, and in the Engineer Update you can see a robot prototype on the wall.

If Valve HAD put in female versions of the classes, they would've had their own specific personalities, rather than being gender-swapped versions of the original males.
Just check out T03nemesis' Deviant ART page and search for "Team Fortress Fan Girls" to see what they may have looked like.

The respawn works like this...
When you die, the medic activates the ubercharged heart, and the engineer teleports you back to base, all patched up.

Little Jack from the Christmas comic will grow up into a badass mercenary
He's already seen the BLU team in action, had a conversation with Spy and killed a man. Perhaps he'll grow up to be a hired gun, even a Spy specifically!

Pyro and Engie don't actually live together
When Engineer's house gets cleaved in half, he says they 'owe him a new house', not 'owe us' a new house. Maybe Pyro was just visiting for Smissmas.
 * Considering a Solemn Vow was on the mantel, one Gunboat was hanging from the fireplace, and the reindeer-antler tree had Sniper's knives and Soldier's grenades on it, and the fact that the mercenaries have been seen living in one place before, it's a safe bet that the rest of the mercs live there too, but they were all elsewhere, or asleep.
 * When had they all been seen living in one place before? Even though I tend to think they live at their base, the comics never seem to show that. In my opinion, they were all just visiting for Smissmas, thus explaining the presence of their belongings, but had all gone to bed. Pyro was too excited about Smissmas to sleep, so Engie was reading him/her a bedtime story.

Underneath the Pyro's gask mask and Spy's balaclava...
They wear a balaclava and gas mask, respectively.

tr_walkway is the RED team's training mode
While the BLU team's training map is small and strict, the RED team's training map is large and open-ended.

Crits are doled out by the Announcer
The Announcer controls both sides, this much is certain. So it stands to reason that she has control over the conditions in which they fight. Crits are allocated to individuals through chips in their weaponry, inserted after the company receives the weapons from Mann Co. that is activated at whim by the Announcer whenever she thinks it would be funny, given to the entire team for a short time as a reward for capturing the Intelligence and as a reward for winning at the end of a round. They can be given out permanently, but the Announcer seems to want permanent, bloody battles, so she has no reason to do that. The Engineer has a basic idea of how to reverse-engineer this technology, having figured out how to give his weapon a limited amount of critical hits with the Frontier Justice, and the Medic has been given a weapon that lets him choose when to get crits, in a limited fashion, but apart from that the technology to give weapons crits rests solely in the hands of whoever the Announcer works for. How else would two corporations be able to take over the entire planet?

There is going to be a video focusing on the BLU team.
When they're not being shot to smithereens, that is. The Announcer mentioned at the end of 'Meet the Director' she would hire another director to talk to the BLU team, so maybe we'll get a Meet the Team video where the BLU team defeats the RED one via the power of teamwork. (okay, maybe not that far)
 * There has been one, sort of: the Mac Update video. That's the only video where the BLU team clearly don't lose. Yet. I posit that the whole RED team winning thing is a reference to Windows being represented by RED while Mac is represented by BLU. It totally makes sense.

In the Team Fortress 2 universe, milliners live the high life
Either worshipped like gods or as high class aristocrats.

Some of the characters have had dealings with magicians in the past.
We already know Merasmus exists and that he can send people back in time. But magic could also explain some of the cast's unnatural abilities, such as Medic's Regenerating Health, Pyro's Hadoken and the fact Heavy can kill people with his finger gun- they made deals with wizards. Or threatened wizards. Or are wizards. Or Pyro is Merasmus.

The teams were a package deal
At some point in time, some or all of the Red(and separately the Blu) team members met, either all at once or gradually inducting people into the group, and decided to team up to collectively bulldoze the competition, maximize profits and make them the world's most badass mercenary team.

Everyone is related to/somehow associated with the previous generation
Either as descendants or proteges of the original. Well, we already know Dell's father was their Engineer...

All the strange stuff in game can be explained using Australium
Basically, most of the things that are brought up in both this section and the Headscrater's one can be explained through the use of the wonder metal Australium. Though it's only been mentioned once (in the Loose Cannon comic), and it's barely explained there, what little we know of it points it to be psyco-mimetic; meaning, basically, whatever you want it to do, it will do. It also is apparently slightly radioactive, and this radiation causes physical changes in those who are exposed (most prominently the growing of impressive moustaches, huge muscles, and a patch of hair on their chest that's shaped like their homeland, as shown by Saxton Hale). Basically, my theory is this; everything in the merc's world (weapons, tool, the landscape, even the merc's themselves) either have Australium as part of their construction or have been exposed to a low level of Australium radiation. This explains;

Being able to get ammo from any dropped weapon by walking over it (Australium can change whatever material it's infused with into something else, instantly)

How the Engineer builds/repairs his buildings with his wrench (Austrailum can be "set" through focused thoughts, meaning that any exposure to more Australium will cause whatever it's in to revert to whatever state it was "set" in. In this case, the Engineer's "metal" is raw Australium, and as he hits his buildings he adds more to it, reverting the building back to it's original state. This is how upgrading works as well; Austrialium can have mutilple "sets", depending on how much Austrialium there is. More metal, it goes to a higher set.)

How the Dispenser, Medi-gun, and Bomb Cart work (the beam is basically Australium radiation, which (as above) sets it's target back to a "set" state, physically, mentally, and equimentally. Which is why the cart and dispenser can't overheal but the Medic can (he simply increases the output of radiation to move the patient to a higher "set", just like upgrading a building). Of course, they can't go beyond this second "set", which is why the medi-gun won't heal the Demoman's missing eye.)

Ubercharge (The Uber-device attached to each class's heart runs on Australium radiation, fed to it by the Medi-gun, and, when activated, covers the medic and patient in a "shell" of Australium radiation. This is why it takes time to charge up. The medic COULD theoretically force-feed the full radiation burst all at once...but the result would be similar to what happened to the Heavy's original heart, but on a full-body scale.)

Critical Hits (All weapons used by the merc's have Australium in them. Sometimes, the latent radiation will transfer to the ammunition, causing additional damage. They can also be created intentionally by feeding radiation into the ammuniction, as in the case of the Frontier Justice and Manmelter.)

The Sniper's rifle "Charge" (Basically, as the Sniper stays zoomed in, the rifle slowly feeds radiation to the round in the chamber, increasing the reactiveness of the gunpowder inside it. This results in a faster round, which does more damage)

Respawn (Upon death, the Australium content of the deceased merc is forcefully removed from the corpse by the machines inside each spawn point, and refromed according to (again) a "set".)

Abraham Lincoln being the original Pyro and the current Pyro's ambiguity are an in-universe coincidence
In actuality, current Pyro has nothing to do with the events with the Manns, and it's a Red Herring Valve are using.

Team Fortress 2 is the Distaff Counterpart of Touhou
They both contain a mostly one gender cast of questionable sanity, have more stuff flying around than world war 2 and breeding pools for countless meme's.