Mo-ri Jin

Jin Mo-ri is introduced as an arrogant, carefree child obsessed with fighting.

However, his true identity is that of the great God Sun Wukong (The Monkey King), the leader of the Mount Hwagwa Monkey and one of the Nine Kings of the Sage Realm. He cannot be defeated by human beings as he is not human himself. To truly defeat him, another Demon or God would have to do that. One of the Japan Team's shaman member states that his future and as well his death could not be foreseen. As of late, his True Form power is above his grandfather.
(Source: God of High School Wiki)