War's stage in the game is Mount Olympus. In the game's Story Battle mode, like many other characters, War's role varies due to the randomized nature of the mode. War can be yet another red herring, having information on the locations of Splinter captive or even the one holding Splinter captive. Other characters such as Fake Brother may state that Splinter is with War but when the Turtles arrive to fight him there is no mention of this in their dialogue. 
In the Tournament mode, his ending simply has him celebrating his success and that the others have been taught to not mess with "intergalactic life forms".
Powers and abilities
Alien/otherworldly physique: War is large, monstrous, and heavily armored with a thick natural purple skin.
Claws: His claws are six inches long and are the crux of most of his physical strikes.
Super strength: Even at 8 feet tall and 350 pounds he has more strength than the average human or mutant of his stature.
Energy Aura: With his War Dynamic super move, War encases himself in a ball of energy and fires himself across the stage, bouncing multiple times in an effort to strike his opponent.