A Demon That Destroys the World, but Will Be Remembered Forever

Senior brother was attacked by junior brother x The senior brother becomes a demon and destroys the world. He turns against the senior brother and becomes an old enemy. However, after the junior brother who has a crush on the senior brother becomes a desperate widower, the senior brother is reborn as a love story. The copywriter holds back a little longer. Purpose: I hope the world will always be peaceful and happy