Reincarnation and journey to the boundless sky

A man named Zhang Kai, from the beginning of his life until his death was full of suffering. He was a criminal and had killed billions of people, but there was a reason for that. The reason that led him to his unfortunate death and the loss of his loved ones, but it didn't end. He moved to a new world with a new identity, revived his old powers and solved a mystery that would change him and everything.