Marrow
From the school of character design called "lets make a new Wolverine," Marrow was one of the more popular grumpy badasses with sharp fighting utensils to join the X-Men. With an enhanced healing ability, Marrow's main power is to quickly grow extra bone mass, be they swords from her back, armor or spikes thrown at enemies. Though only on the X-men a short time, it was revealed she has two hearts and that her other identity dated Peter Parker. Not bad for a freak.
Mega Man
Featured in more games than just about anyone not named Mario, Mega Man is Capcom's biggest star and is currently enjoying a comeback. Built around the simple but ingenious idea of copying his enemies attacks, the robot built to be a boy but forced by circumstances to battle Dr. Wily and his Robot Masters is one of the greatest heroes of our time. No matter what he's facing he always keeps a cheery demeanor, but has his Mega Buster ready just in case.
Morrigan
Morrigan is probably the most well-known character of the Darkstalkers franchise. A bit of royalty, she was born incredibly powerful, so her father locked away part of her power, which she would only receive upon his death. Even after his death and with the throne hers, she would much rather dabble in the world of humans. Not only magically powerful, Morrigan also has the power to transform her bat wings into any number of things, both offensive and defensive.
Omega Red
Created as the USSR's answer to Captain America, Omega was too psycho for the Reds to control, so he was put in suspended animation until Communism fell. Despite being made as a Cap wannabe, his chief enemy is Wolverine and consequently the X-Men. Aside from super strength, speed and agility, Red is equipped with two tentacles made of carbonadium, a more malleable variant of adamantium. The tentacles can drain the life out of people, healing Omega Red. And to top that all off he secretes a pheromone that induces death on most people that come near him.
Psylocke
Psylocke's life is a winding road: born in the UK, she's Captain Britain's twin sister. Manifesting mutant psychic powers and gaining a pair of cybernetic eyes, she comes to the US and joins the X-Men. She got kidnapped by ninjas, was brainwashed and altered to look like an asian crime boss, and when freed got her former mind back and kept all her fighting techniques. On top of those skills, she uses her psychic powers to create blades of energy which don't cut so much as totally screw with your head.
Rogue
Not always one of the good guys, a confused teen Rogue joined the Brotherhood of Evil Mutants but soon left after meeting the X-Men. But that was after she attacked Ms. Marvel and used her mutant powers of life draining and power stealing on her. Unfortunately she held on too long, permanently stealing her powers flight, super strength and invulnerability, along with Marvel's psyche too, which still haunts her. Those powers make her one of the top X-Men, though she keeps all her skin below the neck covered to prevent her accidentally harming others.
Roll
Mega Man's sister, also built by Dr. Light, Roll normally takes the back seat and supports her Mega-bro from the comfort of the Doc's lab. But when she does enter combat, she shows her homemaker side, fighting with brooms and whatever else is on hand. In MVC2, she's basically comic relief, having variations of Mega Man's attacks that are weaker or sillier. Fun fact: her name is based on the fact that Mega Man is Rockman in Japan, making them Rock 'n Roll.
Ruby Heart
Another of the handful of new characters in MVC2, Ruby has a similarly sparse background. Considered the main character of the story, she's a French air pirate who just missed the big pirate popularity explosion by a few years. In the only ending in the game, her ship flies the others into battle with Abyss, the unplayable boss of the game. She wanted the crystal Abyss has, but upon getting it, decides to let it go, dropping it into the sea. Her top attack is the old pirate stand-by of stabbing a barrel.
Ryu
The heart and soul of the Street Fighter series, Ryu is probably the most well known fighting game character in the world. Master of the Hadouken (fireball), he is more out to perfect his craft and hone his skills than win fights. An orphan trained alongside Ken, Ryu has a personality you could call stoic or boring. Either way, he is often seen as the greatest pure fighter in the world, always out for the next challenge to his abilities, with very little else in his way, save for vengeance against Akuma, the man he thought killed his very alive master.
Sabretooth
Wolverine's long time nemesis, Sabretooth is a dark reflection of Wolverine. While Wolvie fights his animal instincts, Sabretooth embraces the animal within, usually in incredibly violent fashion. On top of having enhanced senses, strength, speed and stamina, he also has a powerful healing factor and a set of claws - more like long fingernails - that can cut through most things. An adept warrior, he also doesn't have guilt or conscience holding him back, making him a tough opponent.
