Deadpool is from a particularly peculiar corner of the X-Men universe in the comics. He was introduced as a villain ripping on a DC character in the pages of X-Force, before he got retooled as a pop culture-spoofing assassin who is apparently aware that he's in a comic book and frequently comments on that fact, much to the confusion and/or chagrin of the other characters he's interacting with. A lot of the time he's used to poke fun at the more po-faced, serious soap opera business of the wider X-Men line and whew mama is there a lot of that going on in the X-Men and you can expect him to play a similar role in the film, since Fox have confirmed the Deadpool movie is part of the same franchise. Yes, Ryan Reynolds doing backflips in red spandex whilst directly addressing the movie's director on-camera is going to be taking place in the same Shared Cinematic Universe as Bryan Singer's ever-so-serious first couple of X-Men films, the angsty Wolverine solo flicks, and the upcoming Gambit spin-off starring Channing Tatum. Expect references to all those films, and maybe cameos...?
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/