A game where you play two rivals for different parts of the game that end up fighting each other at the end where you choose which one you want to play as for the final battle.
That or you play one character for like a fifth or a quarter of the game on a mission to eliminate this powerful rival but then once you reach the enemy he/she kills you and you continue as that character, but as you go you realize that the problems you are facing are being orchestrated by the very same character you were for the first part of the game.

Thanks to Blacksaber for the sig!







