Crazy Boss Idea

[CIDE]

I'm going to be seconding the suggestions for things like builds into Ur Priests. It fits thematically and doesn't cripple him mechanically. Via divine magic he could easily have the buffs to emulate other classes lasting all day including the full BAB, some fighter feats, boosts to skill checks, etc. If he's high enough level and has the right gear he could easily be confused for just some high level fighter or rogue the first time he whoops the party's ass.

Edit: While I can't think of any off the top of my head (I JUST woke up and just kind of lazily surfing) there's ways to dip into arcane spell lists.