u can find out what happened to him if u read the comic book Serenity: Those Left Behind. It shows why Book left the ship, why das, badger wasn't in the movie and Mingo and Fanty were and resolves the Hands of Blue plotline.
I really never thought about what became of Badger. I did, however, recognize the actor, who has been in a lot of TV shows--Leverage, Burn Notice and others. He was a familiar face.
