Start by Traveling Through the World of Cultivating Immortals and Becoming the Young Master of the Demon Clan

(Protagonist is insane) This is a world where spiritual energy is revived and everyone can cultivate immortality, referred to as "the world of immortality". Our protagonist Ning Yu traveled to this world of immortality and became the young master of the demon clan. He also awakened the mission system. As long as you complete the system tasks, you can get rewards. With these, Ning Yu became the number one person in the world of immortality. The immortals all called him the demon god! But not so in another world.