NPCs:

Magneto (President Eric Lehnsherr): President and founder of Genosha.
Sabretooth (General Victor Creed): Head of the Genosha military.  Answers to the President.
Mystique (Colonel Raven Darkholme): Head of the Genosha Special Forces division.
Deadpool (Wade Wilson): Contractor working for the GSF who trains the special forces troops.
Blink (Dr. Clarice Ferguson): Intelligence operative that provides information to agents in the field.  Also performs stealth infiltration/exfiltration for the team and works as a field medic.
Wolverine (James "Logan" Howlett): Sent by Professor Xavier to insure that Magneto doesn't start a war.  He works as an actor for the Genoshan military and police forces partly to earn money and partly so that he can make sure the troops won't go along with an invasion.

Future NPCs I might use:  (you can use them if you want, though)
The Avengers (Iron man, Thor, Captain America, Black widow, Hulk, Hawkeye)
Forge
Xavier