The Leveling God
William is one of the most powerful person in the world. He could matched up a god.
One day when he was slaughtering his way into the demons army. The seven demon kings and four divine beast ambushed him. This lead him to fight eleven godlike beings on his own. He fought the demon king and divine beast until his last breath. In the end William managed to kill three demon king and one divine beast before he died.
But when he thought he was dead, he found himself travel back in the time when he was in his teens.