The Daily Life Of A Demon King

The man who has feared as the Demon King Seitan... He is resolute, stalwart, and invincible. His absolute power instills a veritable self-confidence that is only surpassed by his ego. As he grew older and older, His Body lost its capability of being The Demon King. After his Death, He Reincarnated into a new world of Modern Cultivation, which was totally different from Magic. the Demon King has a second chance to relive his life. How will The Journey of the Man who Challenged and Killed the Gods themselves?