Or, you could make him a flimsy character that LOOKS invincible, but really he's only there because he's equipped with stuff the group would like to have but is hard to actually find.
Or you could make him a warforged monk with tons of Con with a necklace of natural weaponry, Ancestral Relic, Item Familiar, a tooth of Leraje, and some levels in kensai. He won't want a "more powerful" weapon when he's got a +25 unarmed strike.