The adopted brother and arch-enemy of Thor, Norse trickster-god Loki plays villain roles in both the Thor and Avengers movies and is already listed as appearing in next year's Thor sequel. While Loki's appearances in the Marvel continuity date back as far as those of his heroic brother, the character's seen very few playable appearances thus far, so we're looking forward to taking control of the speedy, vicious fighter.
Obviously Magneto is one of the most powerful characters in Battle for Earth, what with the ability to control any and all metal on Earth, up to and including the North and South poles. He uses said power to fight for the rights and supremacy of the mutant race, even if he has to fight other mutants--namely the X-Men--to do so. Likely to show up in the game are the character's enormous powers of magnetism and telekinesis, as well as a history that's seen him fight alongside and/or against many Marvel heroes and villains alike.
Phoenix is a disembodied universal force that's manifested itself through various characters over the years. Battle for Earth's Phoenix is modeled on Jean Grey, the ex-X-Man who channeled the force during Chris Claremont's classic Dark Phoenix saga.
Phoenix's powers include traversing and manipulating spacetime, absorbing the consciousness of the entire universe, energy blasts that have destroyed whole planets, and channeling the life force of beings not yet born within our timeline. So she should be a pretty good character to pick if you're unsure.
The Skrull Queen and initiator of the Secret Invasion itself, Veranke is one of the most powerful beings of her race. Her advanced shapshifting abilities allow her to go undetected by the Avengers' security systems as well as (probably more pertinently to this discussion) taking on high-powered variants of her opponents' powers.
Magneto's daughter and the instigator of the comics' House of M storyline that preceded the Secret Invasion, Scarlet Witch isn't Magneto Lite, Thanks to her Hex Magic, she's able to manipulate others' memories, luck and the flow of time, with later storylines involving the character deconstructing and imperiling the nature of reality itself.
Thus far, her playable in-game appearances haven't quite explored the extent of these powers, though we imagine it would be pretty hard to incorporate existential annihilation into a one-on-one brawler. But Ubisoft is clever, so we live in hope.
It's hard to imagine anyone reading this doesn't know the basics of Spider-Man: shy teenager, radioactive spider, implausible superpowers, friendly neighborhood web-slinger.
Besides spearheading the comic film boom of the last decade, Spider-Man's starred in numerous video games--including a few notable non-canonical appearances in the 8-bit era, and a series of high-flying adventures over the last two generations that put the lie to the old adage about licensed video games always being substandard. The character's generally a quick, agile all-rounder, and his appearance in Battle for Earth looks to continue this tradition.
One of the most powerful X-Men, Storm's powers generally tend to get toned down for games so as to give the other characters something to do. The sometimes leader of the X-Men's incredible powers allow her to control weather all over the globe, which mainly manifests itself as shooting lightning and mini-tornadoes at people and hovering just above the ground. Still, we're always looking for new and interesting uses of Kinect, and the ability to cause weather-storms throughout the globe certainly fits that bill.
The Secret Invasion storyline (and thus Battle for Earth's own plot) hinges on a covert invasion of Earth by a hostile alien race, the Skrull, whose shapeshifting powers and advanced combat abilities strike deadly blows against the Avengers and the planet at large. Super-Skrull was originally augmented with enhanced abilities and the powers of each of the Fantastic Four, though his allegiances in the actual conflict may surprise you! Unless you expect he'll be fighting anyone the game sets him against, in which case yeah, he will.
Thor is the Norse God of Thunder, with all the ridiculously overpowered attacks and strained mythological references this entails. While his particular grudge is with treacherous adopted brother Loki, the near-immortal Thor has served as a long-standing member of the Avengers since the team's inception, and as such has fought all manner of foes human and intergalactic alike.
One of the game's more muscular fighters, expect Thor to be a good choice for players who prefer strength over speed and archaic thee-and-thou talk over snappy Spidey-style quips.
Marvel originally got the idea for Venom by paying a fan $220 for the concept, which is pretty generous for the notion of Spider-Man gets a black suit but a low price to pay for what would evolve to become one of comics' most enduring characters.
A longtime foil for Spider-Man, Venom's a shapeshifting extra-terrestrial life-form capable of imbuing its host with superhuman speed and strength. Previous titles such as Marvel vs Capcom have capitalized on this most brawler-ready of abilities, which Battle for Earth looks to showcase in full effect.