"my fighter" is good enough for a name :)

I'd recommend continuing the game with two players. Leave out the guy who doesn't want to play. And if they don't want backstories, then don't try to force them. For one thing, you can role-play without -- just assume the characters are travelers from another country. And for another thing, if the alternative is not playing at all, then take what you can have. Straight-up fighting games can be fun. I've cleared many a dungeon of Skaven in Advanced Heroquest :)

If you want to keep the third player around, and he really doesn't like roleplaying, then perhaps you could try some boardgames.