Roll Player -- A participant in a role playing game who is a self proclaimed master role player (not to be confused with roll player) when in fact they are actually a power gamer. These players frequently use their "character backstory" to justify anything no matter how stupid or game breaking it might be. Though they frequently hide behind the guise of backstory they are almost always unwilling to work at making the game fun for everyone. Sadly they are just min-maxing power gamers trying to hide their devious ways.
(It was here first ... hehe).