Prince of Persia: The Two Thrones

Story related. Cannot be missed.

Once you reach The Arena, you'll have to fight this Giant creature. At the beginning of the fight you won't be able to hit it directly, you'll need to blind it first. To do so you'll have to complete 2 small climbing sections around the arena. Once on top, your screen will flash, press to start a small Quick Time Button sequence. Once both sequences are completed, it will be blind and you'll finally be able to hit its legs. When its life bar is almost empty, it'll stand on a single leg. Quickly slash the other leg to prompt the final Quick Time Button sequence. The trophy will unlock soon after the boss is defeated.