[Talgian]

Cannonball- No clue.

Dr. Doom- Dr. Doom is the dictator of the "enforced monarchy" in Latveria. Incredibly arrogant, but also incredibly smart, he has suffered many hardships in life. As a result of an accident and then putting a burning hot iron mask on his face, he is horribly disfigured, which does not gel with his vanity. Nonetheless, he is very powerful, thanks to his scientific genius and other abilities. I'd expect powers relating to his control over powerful Doombots, mystical abilities like attacks and body switching, as well as other abilities generated from a nuclear-powered super suit, and his genius.

Mystique- Often aligned with Magneto and his Brotherhood of Mutants, Mystique is not too nice. I don't know much else of her background, but Mystique is a shapeshifter. She can change make virtually any aspect of her appearance-including clothes, fingerprints, retinas, etc. She also heals really well and is a trained combatant.

Captain Marvel- Again, somewhat fuzzy here. I'm not sure which incarnation of Cap. Marvel we're talking about here, but it's generally the same story, and powers are pretty much identical. Marvel is an alien who has helped earthlings many times. He has an interesting array of powers, including limited precognition, strength, energy blasts. However, he needs to convert solar energy for these, so without starlight he's significantly weakened, although he still has many high-tech weapons and tools. Powers would probably include strong energy attacks, something tied to his ability to see the future and determine enemies' weaknesses, and his tactical brilliance.

Wolverine- Logan was experimented on by the Weapon X program way back when (his age is in the triple digits). Very gruff, likes cigars. He is an X-Man, and his powers are quite formidable. He regenerates, is very fast, has super strength, and an extremely acute sense of smell. Oh, and these three claws on each hand, part of his adamantine skeleton. I expect his powers in-game to fall along those lines.

Spider-Man- Again, someone you probably know. Peter Parker was bitten by a spider, great power, great responsibility, yadda yadda yadda. Powers include super strength, speed, agility. He can shoot spiderwebs to move fast, tie up enemies, or for any variety of purposes. He's also a brilliant scientist. I'm going to go ahead and guess you all know Spidey well enough to stop there.

Captain Britain- Don't know the backstory too well, but he's very similar in power to Captain America. Britain has the same super speed, strength, and agility as Cap, but he can also fly. He generally has a more mystical feel, I seem to recall something about a wizard or somesuch. He also has some immunity to psychic abilities. Oh, and he's a combat whiz.

Deadpool- A cheap knockoff of DC's Slade, Deadpool is an evil mercenary and combatant. He's also incredibly stupid. Despite that set back, few can match his combat prowess. A premier assassin, Deadpool has a very nifty tricks besides a vast knowledge of unarmed and martial combat. He's got regenerative healing, super reflexes, strength, etc. Powers would likely include lots of ways to kill you, mostly through physical means. He does have lots of criminal contacts, and also a device that allows for minor teleportation.

Mandarin- No clue.

Mathemanic- Uhhh, doesn't need a calculator?

Captain America- Steve Rogers was injected with the Super Soldier Serum, Cap has been the symbol of America and Patriotism ever since. He's got all the super strength, reflexes, and agility you could want, as well as this nifty, indestructable shield. Basically, he's the best possible at physical activities a human could be. Expect powers based on his leadership, unequaled tactical genius, shield throwing/bashing, and good ol' fist-pounding.

Juggernaut- Someone else who I don't know the backstory too, but still wouldn't want to meet in a dark alley. Jugs is usually aligned with evil and the Brotherhood of Mutants. His big thing (aside from his large physical size) is inertia. Once he gets going, nothing, I mean nothing can stand in his way. He also has super strength and resistance to most physical attacks. Like Magneto (and most other people), he is quite vulnerable to telepathic assault, so he wears a helmet that makes him relatively immune, like Magneto. Powers will most likely be based on his inertia, ability to crush you, and various resistances/immunities.

I hope these help a little bit. There'll be more later, but I must be off.