Nemesis

Nemesis is a sword wielded by Sigma Uchiha's Suanoo. It sits in his Susanoo's left hand, while Ajax sits in its right hand. The blade is extremely powerful, as it seems to get more destructive the more angrier he gets. As revealed in his battle with Comato Uchiha and Kaio Uchiha, they were lucky he wasn't enraged, as the destruction would have been much worse.

Trivia

 * The power of the blade is taken from the actual Greek god, as he wanted revenge each time her was angered. The blade however, in turn for being angered, gets more destructive.