Originally Posted by Yora
Sounds a lot like one case of The Only One Allowed to Defeat You .
Nah, I don't think that would apply here... This refers more to... like bad guys or rivals joining with the hero to defeat some other threat so they can beat some other bad guy... or something like that.
Actually, I don't think this has a name yet. Or... any subversion I can think of. Though, naturally, the final battle has to be in some kind climatic, if the tournament gets finished, that is.