Idea:
A standard action/adventure game. Go around, beat bosses, get golden whatevers. Take them to your mentor guy. Find out he wanted the whatevers so *he* could be super-powerful, not for any noble purpose.
Spend the rest of the game going around to the bosses you beat, doing quests to apologize about beating them up so they'll help you beat the final boss.
This is where someone tells me that game exists and is some popular title I've never played