He dad was "adusive" and forced his to punch rocks until they spit in half so that he would be strong enough to control his demon form and destroy the world. And his eyes? He once fell into a crave which held the original owner of the demon (since the megalodons passed it down until they died off) and once he stared straight into the demons eyes, his eyes became orange and turning his pupils white (which was WAS F**KING EXTREMELY RARE since every other creature who did it DIED) he was haunted by the demon until he destroyed his father (since any raging emotion with control the demon) once he won. The demon bowed before jaws in the pitch (his mind, there telepathic) and has full control over it, but since he has anger issues. He loses control sometimes.. And HE KILLS EVERYONE IN SIGHT WHEN THAT HAPPENS, he has the power to destroy and create worlds (and literally anything else) he's still going through the pain of everyone counting on him to protect them
But he can't help his evil side from killing innocent people from all the rage from the past.
He's kinda a neutral when is comes to evil and good