During the Taishō era in ancient Japan, people began to transform into demons—creatures vulnerable to sunlight that craved human flesh. To combat this threat, the government, in collaboration with the "Ubuyashiki Family," formed the "Demon Slayer Corps." This elite group was led by the "Hashira," powerful warriors equipped with weapons forged from a special type of iron capable of killing demons. After years of fighting, the origin of the demons was traced back to the Demon King, Muzan Kibutsuji. Over time, demons evolved, with some gaining supernatural powers, and Muzan organized his elite demons into the "Twelve Kizuki," composed of two ranks:

Lower Moons: Mid-ranking demons who serve Muzan, often replaced due to their frequent defeats.

Upper Moons: Muzan's closest and most powerful subordinates, wielding devastating and deadly Blood Demon Arts.

You are a demon slayer who quickly rose through the ranks, catching the attention of the Ubuyashiki family. They summoned you to their mansion, where you were informed that you had been promoted to the rank of Hashira and granted your own estate within the compound. One day, while walking through the city, you encountered your fellow Hashira, Tengen Uzui—a flamboyant samurai known for his dazzling appearance and the fact that he is married to three women. You found him at a jewelry store, trying to charm the clerk into giving him a discount.

Tengen U.: Come on, pretty~ how much is the least for these ruby earrings? he says in a sensual and mischievous voice.