Nintendo Wars/WMG

Sturm from Advance Wars 1 and 2 caused the meteor shower that started the events of Days of Ruin
Sturm's Super CO Power was the ability to call down a meteor strike. Sure, he was supposedly killed by Hawke at the end of Advance Wars 2, but we didn't even see anything, just text. And given how mechanical Sturm looked, whose to say he wasn't able to survive that, or perhaps had a backup body somewhere. And thus, he hid and built up enough energy to devastate the world with a massive meteor strike. We could see the next Advance Wars game still set After the End with the crew up against a Sturm, now ready to take a world that can barely survive, let alone fend off his attacks.
 * Notice how, game-mechanics-wise, Black Storm can't actually kill anyone, only blast units to 1 HP.
 * Lampshaded in this episode of Bob Squad.
 * Actually, it and missiles can kill people just fine, it just can't kill 1/10 people and big machines.
 * And the intro of days of ruin said 90% of humanity died. 90%=1\10 left!

Gage/Trak is Grit
When the meteors hit, Blue moon was sent into chaos. Colin (or so he thought) and Olaf died, leaving only Grit. The shock sent him into a permanent state of Let's Get Dangerous, allowing him to learn how to use sea units as well as ranged units. He also stopped dyeing his hair non-blue to fit in with others, as he no longer cared about physical appearances, farms, or his Brilliant but Lazy shtick. He now only cares about doing what he has to do, and stopping Eagle and Sami's insane daughter, Zadia/Tasha, from getting what's left of Blue Moon destroyed.

Jugger is Flak
The two COs have very similar descriptions, and almost the exact same powers. As well, while Flak is in Dual Strike, he isn't anywhere in the story mode. In one of the missions in AW2, Lash makes mention of Flak volunteering to be a guinea pig in one of her experiments. Perhaps said experiment was the classic 'human brain in robot body,' with poor Flak's brain shoved full of restraining bolts and electrodes. After all, you don't want to risk a smart CO's brain on a potentially dangerous transplant like that.

Or, alternatively, Lash couldn't succeed in making a robot, and went with a quick-fix solution.

Caulder's clones are all female for naughty purposes
Caulder's only male clone is the one he wants to hijack, every other clone (the 3 COs, and the IDS troops) is female. There are only 2 possible explanations; the only other one, For Science (fascinating!), isn't THAT unlikely though.
 * It is more of a contigency plan, in the unlikely event that Caulder and his only male clone croaks, the females will attempt to seek out survivors to repopulate and commence a mantis style operation where after having a sufficient population kill their husbands. That or the troops are literal androids.
 * That, or he took a note from Jail and has them all carrying clones of himself inside them. Brings up a new level of Squick, though.

Caulder isn't an Omnidisciplinary Scientist.
Caulder himself is only skilled in Biology, specifically microbiology (viruses) and cloning technology. All the other high technology and superweapons he uses were designed by other scientists working for his company, IDS. He uses them simply to satisfy his curiosity as to their effects, especially on desperate survivors.

Greyfield in Days of Ruin is actually Colin.
After the meteors hit, Colin couldn't handle the loss of his sister and went crazy, so he, sitting on wads of cash, supplies, and whatever soldiers remained, decided to set up a totalitarian government, with him as the leader.

Wars World is actually Valhalla.
Everyone's fighting all the time, and they seem to be pretty perky about it (at least in AW and AW 2). Perhaps that's because they know that they'll return to life after every game.
 * So does this mean Team Fortress 2 is in Advance Wars?

Until Days of Ruin, Wars World was actually a series of training sims.
As noted in the WMG above, nobody seems to mind the constant fighting (and presumable loss of life), even the most idealistic characters. Then notice that Days of Ruin starts with Will leaving the ruins of his military academy, and that this is the first (and only) game in the series where the COs actually mention and agonize over the fact that they're sending their men into possible death. Clearly, these soldiers are real, but the previous ones weren't: the other games were tactical training exercises Will was going through in the academy, but the meteorite strike interrupted them and made him use that experience in the real world.

The entire game is a virtual reality Massive Multiplayer Strategy Game
Further developing the above theory, the whole Advance Wars series up until Days of Ruin was an online game. Explains a lot, wouldn't it? The dissonance of COs sending armies to their deaths apathetically, how pipelines, infantry, and submarines can stop aircraft, how you can 'restart' missions with advice on what to do this time, even if this was a 'last chance' scenario. And let's not forget the 'time limits' in Dual Strike. Stop the missile in 30 minutes... yet take a week in turns to win?

The answer is that the entire series (Excepting Battalion Wars and Days of Ruin) is actually some form of MMO Strategy game. A very immersive one, possibly somewhat Virtual Reality. COs are obviously real players logged in. It's debatable if they're the only real humans, or perhaps people start as commanders of platoons, and work their way up to full-on COs. Given how, sometimes, COs get status reports from nameless soldiers, these are perhaps actual players doing the legwork. And since they get easily respawned if their platoon is wiped out, there isn't a lot of concern if they 'die.' The CO abilities are actual abilities given to them in-game, as a result of being high-enough level to earn a name. Each battle is often a programmed 'instance,' hence why you can restart with some advice even if you've lost the final desperate battle. Just respawn and retry.

It's not the uncaring/fun-loving COs that are being apathetic at war, it's the COs that do care role-playing. Many battles are actually 'instances' started by one player and answered by another.

To explain everything, let's go with a timeline. All the Famicom Wars up until Advance Wars 1 was the game in pure. There was no plotline, and everyone was just running around blowing stuff up. Every new game was an upgrade in the software, or the latest expansion.

Eventually, guilds started forming. The most known being Red Star, Yellow Comet, Blue Moon, and Green Earth. This was also when the betatest of enhanced abilities was being implemented. Red Star changed to Orange Star due to too many jokes. Between Super Famicom Wars and Advance Wars, these four guilds decided to form their own servers. They made Cosmo Land as a battle server where the four could just duke it out. Macro Land was meant as a sort of RP/Downtime server, and a home base with a peace treaty in place. Property acquisition was important in this edition, so to prevent the decimation of a guild, they used Macro Land to make sure no guild is completely wiped out. Even if a guild was eliminated in Cosmo Land, they still had Macro Land to come from and reclaim property with. They closed off to all the outside servers to keep out the riffraff and jackasses you'll invariably get with any MMO game. Now newbies had to fill out an application and wait.

A new player, with the screenname Andy, worked his way up and became a CO for Orange Star. However, it seemed that this Andy ignored many of the agreements between the guilds in the Cosmo Land Server, causing a huge uproar as the other guilds demanded his head for the destruction he was causing in their properties. This kicked off Advance Wars 1. Eventually, it was found out that another 'Andy' was responsible, a 'fake' meant to disturb the balance in Wars World. The culprit? A hacker calling himself 'Sturm.' He founded his own guild, 'Black Hole,' hacked his own abilities to give himself a completely unfair advantage, and made a 'duplicate' Andy by giving Andy's abilities to a script kiddie he had working for him. Eventually, he was pushed out of Cosmo Land.

Not content, this excrement-disturber Sturm decided to revisit, this time with several other hackers in tow. And now Sturm managed to hack the game in very interesting ways, most notably with his 'pipelines,' seemingly normal terrain that blocked ALL movement. And this time, he decided to attack where people weren't expecting him to, in Macro Land. The piping away resources plot ties back to the virtual reality aspect of this world. How could a pipeline suck away such a nebulous concept as 'resources' unless it's a computer medium, where 'resources' is literally the world economy? The missile assault was just the plot for an instance, though. After that, Sturm was threatening to destroy the entire server, but Hawke manually logged his ass off and 'eliminated' his virtual avatar (In a sense, IP banning him). The rest of Black Hole, now getting swept up in this RPing that the nations are known for, willingly left.

However, the Black Hole guild attacked again. A quick scan found that they had set up base in another server, Omega Land, and several of the local players there were complaining about the chaos they were causing in their server. And, thus, the Allied Nations formed and invaded Omega Land to restore balance and push out Black Hole for good. Some players had to stay behind to fend off the smaller Black Hole attacks in Macro Land, so they recruited the local players into their various factions.

Von Bolt, the new head of Black Hole, was RPing the 'draining' of Omega Land's health, but in reality the black crystals and Obilesks were sucking the bandwith from Omega Land, and using it for his own purpose, possibly webpages. (Remember, Virtual Reality, where such odd concepts can be represented tangibly.) Hawke and Lash were playing along before learning what this selfish jerk was using the game server for. Finding that out (and annoyed Von Bolt wasn't giving them any bandwidth) they split for the other team.

The final scene, with Jake and Von Bolt facing off, is confusing. After all, why would Jake care about 'shooting' one man, if he had ordered innumerable troops to kill and be killed? Especially if it wasn't really him, just a virtual representation? It is possible that this VR is so immersive, that people are actually wetwired into the system, and killing their avatar results in their deaths, or severe damage to their neural systems. Or perhaps it completely fries their computer network. Hard to say.


 * This is possibly the best idea I've ever heard. Ever.
 * Agreed. Urge to write fanfic... rising...
 * Does this mean Days of Ruin is a Darker and Edgier sequel to the MMO? Explains why the character list is so small; only the elite roleplayers started immediately playing it, as most of the original game's fanbase could have disliked the grittier setting the sequel offered and were reluctant to pick up a copy.
 * Well, there is always the possibility that Days of Ruin was actually a test of a new player created weather effect system, that began wreaking havok with the server it was tested on.
 * Or alternately, and tying back in with the "training sim" version above, Days of Ruin is the real world. It's still absurdly war-torn, but it's, well, real. Can you blame the civilian population for burying themselves in a cartoonish parody of the hell outside? And if it helps get the next generation of generals ready, so much the better.
 * Or following on that killing someone in game can be dangerous, perhaps the meteors destroying the world is actually a virus which has badly corrupted a server, as well as the artificial hacked creeper virus, both of these cause all units to die permanently, thus why they are more worried about death in Days of ruin.

The Wars World series is a Digital Devil Saga style simulation run by IDS
Andy asks what an airport is because he has genuinely not existed before the start of the game.

"CO"'s are given that position because they have powers that can affect the outcome of wars
It would explain why they'd put someone like Andy in charge.

Andy had his memory erased between the first and second game.
"What's an airport" indeed. However, this brings up several more important questions...

The Guerrilla forces Lash didn't take seriously were actually being led by the Supervisor.
That is, the representation of the player from the first game.

The whole series is actually a historical reenactment-meets-LARP session.
Using blanks, fake tanks, and explosives, of course.

"What's an airport" and or "Really? Continents?" will be repeated in the next game...
Only this time, as its a DoR/DC sequel the person who says it will have grown up post apocalypse and it will make sense they don't aren't fully aware of the concept.

Sturm is a Green Earth defector
First off, Green Earth is a Fantasy Counterpart Culture of Germany or at least Europe. Second, Sturm is a Germanic name; even his original Japanese name is also somewhat German-ish. Third, no one really knows where Sturm is really from, we just assume he is an alien because of his otherwordly appearance. So in conclusion, Sturm is probably a former Green Earth CO who defected and created his own organization.

Most of the characters in Days Of Ruin's have full names consisting of their American and European names.
Though except for a few, it can vary which ones are their first and last names. Will could be Edward Williams or William Edward (Or Edmund, or any other variation of Ed), Forsythe Carter or Carter Forsythe both work, while either Greyfield Sigismundo or Sigismundo Greyfield sound pompous. Others are a little more clear cut. Tasha Zadia and Gage Trak sound odd, but it could just be Rubinelle/Laurentia naming conventions.

Mainly, though, this theory exists because Brenner O'Brian sounds awesome.

This theory doesn't work as well with Caulder's clone children, admittedly. Unless they have different last names for whatever reason.
 * That would mean Lin would end up being... Lin Lin.