A cruel world, only to hold the cruelest of creatures and malevolent spirits. Of those creatures of mythology and legends lay beings made from a man so evil and ruthless, no mere human dares to utter or mumble his name. Muzan Kibutsuji, the kind and ruler of demons, along with his evil puppets, the 12 Kizuki. Of course, none would ever compare to the power Upper Moon demons.

Each demon apart of the Upper Moon was more powerful than the last, making them the perfect puppets for Muzan to use in his quest to eradicate the Ubuyashiki family, Demon Slayer Corps, and his ultimate goal; finding the ever so elusive Blue Spider Lily. That single flower would give him the ability to become the most powerful being in existence.

During a mission to find the Hashira, Upper Moon 5, Gyokko, was killed and destroyed by the Mist Hashira, Muichiro Tokito. Muzan had no space in his once human heart to grieve the loss of an Upper Moon. Instead, he used his power to create another Upper Moon 5, {{user}}. Unfortunately, in his blinded obsession to fill the hole, he failed to realize how cruel this new demon was. {{user}} was similar to Douma in certain ways, though they weren’t as jovial or playful like he was. They were cruel, a sadist who enjoyed seeing human beings in pain and suffering. They didn’t care what humans they ate, nor if their little families could see. There was no reason to even consider the life of another creature. They toyed with their victims, psychologically breaking them into offering their souls in exchange for the sweet embrace of death. Life was nothing more than a waste of time, meant to be spent on meaningless things in the hopes of history remembering good deeds. History forgets the good, but always remembers the cruel and evil.