Deadpool is a character in Marvel Comics. He is a mercenary by trade, and has played both for and against the X-Men. He is most often written around X-Men storylines, due to similar origins as Wolverine (character). Ryan Reynolds plays Deadpool in the 2009 film Origins: Wolverine.
Deadpool is one of the few comic book characters to often talk directly to the audience. His dark humor and pop references round out Deadpool's personality.