Kid Icarus: Uprising/WMG

Dark Pit was formed from a Dark Mirror
In the trailer, he is shown in a purple room consisted up of glass, presumably, mirrors. Perhaps the mirror was an evil magical device set up by Medusa in order to create an evil clone of Pit, like in another well-known Nintendo franchise. Somewhere along the way, Dark Pit decided to have his own purposes and turned neutral.

By defeating Medusa in the first game, Pit released her again.
While there's not much to go by, Pit defeating Medusa in the first time may not have killed her, she was trapped in a Gorgon Statue for most of the game, so in defeating her, Pit didn't stop her, he released her and she ended up being at full power many years later.
 * Jossed: The recent trailer has Palutena saying that Medusa's followers resurrected her, so it's likely she was actually killed. Though freeing her from the statue might still have facillitated that.
 * "Killing" a Demon/Goddess is usually less effective than Sealing them.

Meta Knight will be an alternate playable character in Kid Icarus: Uprising
It would be Crazy Awesome. And there are several reasons this might happen. Sakurai, the creator of Kirby, Meta Knight's series, and Super Smash Bros, where Meta Knight is featured prominently in the story mode of Brawl. Meta Knight would be able to take part in the flying missions because his cape turns into a pair of wings. As for weapons, he already has a sword that could shoot out beams, which was one of Pit's new weapons. Meta Knight could probably master any of the other weapons that Pit can use.
 * Seems probable...
 * Alternatively, there will be a Shout Out to the Kirby series, most likely in the form of an enemy, or maybe a background decoration. (A statue or carving, perhaps.)
 * I can't see this happening.
 * Jossed.

Alternatively...

Samus will be a secret character
Samus already has a range-heavy fighting style, and the dash maneuver in Uprising looks strikingly similar to the sense-move from Other M. Flight could be handled by space jumping repeatedly. The game already has komaytos and star pirates, so a Samus appearance would fit right in.
 * Jossed.

Medusa will turn back into a giant cyclops.
We are now used to seeing Ganondorf as a human for most of the game before facing a variation of his iconic giant-pig-monster self during the final battle. The same thing will happen with Medusa in Uprising and subsequent games. It will only be a matter of time before the Ganondusa shipping community is born and every combination of forms gets tested.

Magnus is based off of Hercules, or Hercules or someone based off of him will appear in Uprising or a subsequent game
He's one of the most famous figures of Classical Mythology, so it would not be surprising for him to make a appearance in some way, maybe with a different name.
 * Heracles is more known for a club than a sword. Then again, Medusa wasn't a goddess...
 * This is what I thought too. Hercules is pretty much synonymous with strength, and personality wise both Hercules and Magnus are manly men.
 * Although Magnus' sword is treated like a Club when Pit is wielding it...

Magnus will eventually side with Medusa
The game mentions that he's in it for the money, and Medusa certainly has resources to spare. The question is, will Pit have to fight him, or will Palutena make a counter offer?

There are more enemy forces other than the Underworld Army.
There is already the Star Pirates and Dark Pit, so there could be more forces that are unaffiliated with Underworld Army.

There is a Bigger Bad greater than Medusa.
Whomever it is, might have used her and her forces as a distraction in order to hide their own objectives.

Palutena created Eggplant Wizard and Tempura Wizard. She hasn't told Pit this.
The monsters Palutena creates when she cooks bear a close resemblance to everyone's most frightening food-based mages.

Hades is Reaver.
Given the similarities in voice and personality, perhaps Reaver made enough deals with the powers of darkness that he became a full-blown evil god?

Dark Pit is the Original Pit.
Okay, in the ending of Myth and Monsters, Original!Pit flew too close to the sun and fell. In Uprising, New!Pit (in Uprising and Brawl) seems perfectly fine, wings and personality intact. Original Pit had been burned by the sun, causing him to plunge to the ground and die. Somehow, on the ground, a copy before he was burned was made of him, including all his memories of his battle with Medusa, of the first Kid Icarus, etc. Palutena comes looking for him and instead finds New!Pit. Both are mistaken that our Pit is the true and only Pit, and he's taken back to Skyworld. Meanwhile, Original Pit spends several days in pain, dying, which severely twists his personality. Eventually, he dies and is forgotten. However, in Uprising, there is a mirror called the Mirror of Truth. When New!Pit went in front of it, it reflected the true person that he was a copy of, not only, in a sense, reviving Original!Pit/Dark Pit, who, after his burning wings ordeal, has a much darker personality. Dark Pit thinks that New!Pit has stolen his identity and definitely isn't happy about it -- so he seeks his revenge. Or something.

Uprising (and by extension, the original game) is part of the Disgaea multiverse.
The No Fourth Wall-ness is kinda remincent of the Disgaea games, doncha think?
 * Total support. As if this picture jokes at that.

Palutena is a Time Lady, Pit is her companion, and her staff is her TARDIS.
Moreover, Medusa is a renegade Time Lady, plus is The Master.

The Space Core's father is .
They both reunited happily together in the endless reaches of spaaaaaaaaaaace.

This might actually explain why keeps helping Pit during the times where he needs it such as when  and ESPECIALLY when.
 * Furthermore, even Palutena.
 * I'd say 's blatant denial proves it. Hell, Pit even tells her that he doesn't think she's all that bad either, before she tells him to keep his voice down. And this happens in, before , and.

The events of The Subspace Emissary are canon.

 * It would explain how Pit and Palutena seem to know so much about other Nintendo games. For example, aside from breaking the fourth wall, it doesn't make much sense for Pit to know about Metroids. Therefore, Samus probably told Pit about them at some point. Plus, some of the enemies in KI:U look a bit similar to the mooks encountered in SSE.
 * It would make since given that Pit knows about Super Smash Bros and how in the JP trailer, Pit and Palutena are shown choosing a character to play. Notice how Pit picked Mario and Palutena chose Kirby? It's obvious who Pit was cheering for during Subspace Emissary. Also, out of all the locations, Pit seems to be the only character that is away from Subspace Emissary given that the Subspace minions only start appearing when Pit is down on earth with the other Smashers and never go beyond a certain point as shown with the Great Maze.
 * Wait... No one in KI:U turns into a trophy upon death...
 * Maybe Palutena lost contact with Pit after he exited Skyworld, which would explain why Pit acts on his own without thinking and when, if Palutena was there, Pit probably wouldn't have been in that situation since Pit established that if something were to happen to him, Palutena would be watching him no matter what, and the only way for the situation to happen is if   was powerful enough to block Palutena from reaching Pit
 * That or maybe Smash Bros. is a spinoff series and has no continuity when it comes to plot.
 * Or, since Pit and Palutena are both aware that they're in a game in Uprising and are shown to know about the other games, the events of the Subspace Emissary are only partially canon. When Pit leaves Skyworld, he's entering the SSE universe and joining the brawl, meaning that he's now limited by Brawl's gameplay.
 * Pit does say that he used a bow in his last brawl. He wasn't hurt; it was a smash!

It's a farfetched theory but here goes. That's only the first portion. The second portion is

Medusa was partially right about Palutena.

 * Concerning her "The Reason You Suck" Speech in chapter 9, Medusa has brought up some good points about Palutena that makes it seem like she's not as innocent as Pit makes her out to be. In the original game, all we get about the relationship between the two is they ruled together, but Medusa hated humans and made their lives miserable. Palutena retaliates by turning her into an ugly gorgon and said that it reflected what was in her heart before banishing her to the Underworld. However, when you look at this game and find out that almost all the Gods and Goddesses seem to hate humanity, what Palutena did seems like a Disproportionate Retribution given that Palutena only gets Medusa for her actions in the past, but with Pit serving her, she can deal damage to every God and Goddess that try to harm humanity as shown when she  In other words, Palutena might as well be a Knight Templar for humanity while   is a Knight Templar against humanity.
 * That's only about her view of the humans, but when, everyone except Pit doesn't act surprised when   Why is that? It's simple. Given that she and Medusa did rule together at one point, it was brought up that while Medusa made lives miserable, Palutena didn't do much to begin with as Magnus states in chapter 2 about how she's slacking off with her duties and that his world is on the verge of collapse because of her (and Medusa). Palutena's response? She calls him a jerk and Pit actually seems shocked by that. Hypocritical much? Not trying to make Palutena a victim of Ron the Death Eater, but given that the game has thrown multiple instances of her doing questionable acts and called out by everyone except Pit, it's not hard to see that Medusa might be right about the two being Not So Different.
 * A jossed theory concerning chapter 24 was that  Even if the theory is jossed from the idol information, it doesn't change the fact that if you didn't have the idol
 * Finally, given that Palutena is based on the Greek Goddess Athena, it's not hard to see Medusa as a victim too given that there are some stories in Greek Mythology that claimed that Athena was jealous of Medusa beautiful appearance and turned her into a Gorgon before ordering Perseus to slay her. When you sum it up though, Pit's black and white view of the world falls naught and Medusa probably suffered as much as Palutena did when she banished her that can't be hidden even with Pit's Shut UP, Hannibal speech to her.

Following the above theory, Medusa is actually more sympathetic then she lets on...
Not trying to turn Medusa into a Draco in Leather Pants, but this troper would like to think that she's a Broken Bird type of character with these reasons.
 * The short anime Medusa's Revenge was supposed to explain why she pulled a Face Heel Turn, but what we get is a glimpse of the past before Palutena turned Medusa into a monster. Notice how Medusa told Palutena to stay out of her affair? This troper would like to think they were in conflict and Medusa's way of relieving stress was to take out on the humans. As a result, it looked like she was just playing on a game board and being the game master, killing humans and destroying buildings. If there two parts to this anime portion like Thanatos Rising then we might have found out that was a bigger reason to why Medusa was banished instead of harming humanity because given the above theory, it's overkill to be banished for killing humans when all the other Gods/Goddesses do the exact same thing. Also, given that they're supposed to rule together and Palutena was supposed to take care of the humans to make sure they would not suffer, what was Medusa supposed to do if she was already Goddess of Darkness?
 * When Medusa defeated Palutena in the original game, she didn't kill Palutena. Why is that if Palutena was the one that made her life miserable? Given the anime said she was imprisoned in her own home, chances are that Medusa would probably want to make humans miserable and stop Pit from getting to her while trying to talk to Palutena about something. The conversation she had in chapter 9 seemed to be suppressed feelings during that time period that she let out during the final battle and before Pit interrupted her, she acts like Palutena betrayed her.
 * Now think about it. Medusa in the anime short calls Pit "Palutena's precious pet" and acts jealous when she says that. Medusa might not have had someone as loyal or caring as a friend/sibling/child like Pit and she was killed twice so Pit could protect Medusa. The fact that Dark Pit was probably created to be a copy of Pit to serve the Underworld but chose to remain neutral hints that she might have wanted someone that would serve her and would never betray her like Palutena.
 * When it comes down to it, something was not resolved between Palutena and Medusa and they both know this which would explain why Palutena won't say anything during Medusa's "The Reason You Suck" Speech and allows Medusa to hate her given that Palutena probably knows she too is in the wrong of her actions.

Pit is Palutena's Morality Pet / Morality Chain.
If it weren't for him, she'd be (and may have been once) just another one of the Jerkass Gods. Love of any form could be a reason here; but it's likely for a far more simple reason. The gods are lonely. They can't trust each other; and mortals are just too short-lived to invest in emotionally. Pit is someone Palutena can talk to who won't die in less than a century; and none of the other gods have anything like that. And that's far more precious than anything.
 * So what about then? Or, if we're really going out on a limb,
 * Supported by the dialogue in chapter 15. Palutena and Pit have a heartwarming conversation only to be spited by . Palutena gets angry with them and say that they wouldn't understand what it's like to have someone like Pit. And it's true. The Gods are shown to not have someone by their side like Palutena and as a result, they act out on impulse. Additionally   Concerning the other Gods/Goddesses though this troper is certain that   Finally

Despite Palutena's claim, Dark Pit's soul is either equally pure as Pit or even more pure.
This idea stems from the fact concerning Pit and his dark side. So if Pit is the defination of Incorruptible Pure Pureness in the KIU universe then that means that Pittoo also has the same pure traits but more subdued. For one thing, Dark Pit is neutral at best instead of being pure evil like the other Nintendo hero counterparts (which shows that despite being heroes, their dark side shows that there is indeed evil in their hearts in contrast to Pit who knows no evil and can only manifest someone that is neutral at best. The main point though of this WMG is that  Now according to   This might mean that Dark Is Not Evil in the purest of forms. "I'd love to get my hands on Pittooey's soul. So dark, so chewy, so malleable! A powerful soul like that shouldn't be wasted on Ol'Chomper's lunch."
 * himself has stated how 'delicious' Pittoo's soul is in Chapter

Pit isn't actually an angel--he's part chicken.
According to the folks over at GameFAQs, Pit is indeed part-chicken. Think of all the chicken references in the game that compare Pit with a chicken. And can chickens fly? Just barely.
 * Does that mean that Dark Pit is also a chicken?
 * Well, there ARE such things as black-colored chickens...

appears to be made of a plasma-like substance, just like the Space Pirates, whose idol states are actually energy beings. He also flies through outer space; and he mentions, which is a definite connection. My guess is that, either during the initial raid on the Space Pirates' ship or most of the Space Pirates (save at least one) ended up being killed.

Another farfetched theory that is similar to the Medusa theory above combined with the knowledge of Greek Mythology. Even though  is a Complete Monster, it's very easy to forget that he is one given that he's Laughably Evil. However, there are some hints that he wasn't always insane.
 * What Pit tells
 * doesn't seem to mind the idea of teaming up with the other Goddesses to  Sure he said he's only working with them because the earth was his and he would be the one to plunge the world in chaos and despite trolling Pit the entire time, he does help out during those chapters despite being...very greedy about it. In comparison to the   who are supposed to be more evil than any of the Gods and Goddesses combined,   doesn't seem that bad...then there's the fact that   If you ask this troper, it would be unfair to label him as a Complete Monster in the first place given that all the Gods and Goddesses minus Palutena seem to hate humanity and it wouldn't be out of character for any of the Gods or Goddesses to   given that this happened often in Greek Mythology where these divine beings are known for using humans in their squabbles against each other (such as the Trojan war).
 * doesn't seem to mind the idea of teaming up with the other Goddesses to  Sure he said he's only working with them because the earth was his and he would be the one to plunge the world in chaos and despite trolling Pit the entire time, he does help out during those chapters despite being...very greedy about it. In comparison to the   who are supposed to be more evil than any of the Gods and Goddesses combined,   doesn't seem that bad...then there's the fact that   If you ask this troper, it would be unfair to label him as a Complete Monster in the first place given that all the Gods and Goddesses minus Palutena seem to hate humanity and it wouldn't be out of character for any of the Gods or Goddesses to   given that this happened often in Greek Mythology where these divine beings are known for using humans in their squabbles against each other (such as the Trojan war).

The reason for Pyrrhon's ...
This is another theory that might give some insight on Pyrrhon's character in the game based on some of the dialogue. This troper thinks that the reason that Pyrrhon  is because he wants respect from the Gods and Goddesses.
 * Pay attention to how Palutena,  treat Pyrrhon.   treats him with great distain and calls him useless,   while subtle at best, acts like he doesn't exist most of the time and even Palutena calls him out on his stupidity and tends to forget him the most of the three. Now despite being the "sun god", he seems to be looked down upon and seems to be weaker than the other Gods/Goddesses. As a result, they don't treat him with any respect. Pit seems to want to know more about him but Palutena dismisses him upon introduction.
 * He might not be the sun god at all. The trio of Gods/Goddesses don't listen to him when they say he's the sun god even though he's shown to use fire magic and use The Power of the Sun. Now look at Greek Mythology and look at the Sun God Helios. He isn't considered a member of the main twelve Olympus Deities given he's a Titan. However, Helios and Apollo are often confused on who is the sun god. But looking at Helios and his history, it wouldn't hurt to assume that Pyrrhon is one of his many children that inherited his powers, but not his title hence why the other Gods/Goddesses look down on him.
 * This is supported by Pyrrhon's Idol, which refers to him as "the self-proclaimed 'Sun God'" and his "boasts of divine lineage [as] hard to swallow." With that in mind, it seems probable he's not divine at all, but some variety of sorcerer or alien being.
 * His attitude toward Pit. He's the only God that treats Pit like an equal instead of making fun of him like every other character has done in the entire game. Why is that? Well, when you look at Pit's relationship to the other Deities, he may be the Chew Toy but they achknowledge Pit for his strength and reliability  despite being an angel that can't fly. Pyrrhon however can't even get the other Gods/Goddesses to show any respect toward him despite being one of them.
 * With this information Pyrrhon  might be a case of trying to finally be achknowledged by them as some of his quotes ingame imply. Also by   that would make him stronger than Pit who the three at least achknowledge him for all of his worth.

Poseidon will turn out to be a Chekhov's Gunman in the sequel

 * They introduce a major figure in Greek Mythology, give him unique artwork and voiced dialogue, and yet only have him appear in one chapter, never to be mentioned again afterwards? That seems a little suspicious if you ask me. If there's a sequal, I'm willing to bet he'll be giving a much larger role, maybe even being a major villain. After all, his views on humans are very similar to  and it's shown that   hasn't gone back on   views in the ending. Maybe they'll team up to Kill All Humans?
 * Poseidon doesn't seem to hate humans, or at least doesn't hate them as much as Viridi does. He simply acknowledges their flaws, and is willing to help Pit and Palutena save them from the Underworld Army. And while implied, it's never flat out stated that Poseidon killed the humans that lived in the town, only that he sunk it. The humans could have escaped to safety.

The Big Bad of the next game will be either Zeus or Poseidon

 * Related to the above. Both were Jerkass Gods in the original myths, and since it's already been established most gods in this universe are Jerkasses anyway, it kinda fits. Zeus' mysterious abscence in Uprising will be a plot point.

Humans are unable to shoot beams and/or lasers from their weapons.
Perhaps mythical beings and monsters just have the ability to garner energy to shoot while humans typically lack the skill.

Pit has a crush on Palutena
Aside from his Undying Loyalty, there's also his Sanity Slippage where when he imitates Palutena he says "your too handsome to lose." Seems like he has a crush on her to me.

Pit is actually Frank West
Think about, both of them can use almost anything as an effective weapon, they both consume regular foodstuffs to regain health, they both fight massive undead armies, and they both love snarking.