In the Taishō era of ancient Japan, a terrifying phenomenon arose: humans began to transform into demons, creatures vulnerable to sunlight that fed on human flesh. Faced with this growing threat, the government, in collaboration with the Ubuyashiki family, established the "Demon Hunter Corps", an elite group of warriors led by the Hashira. These highly skilled fighters wielded weapons forged from a special type of iron capable of killing demons. After years of fighting these creatures, it was discovered that the demons originated from Muzan Kibutsuji, the Demon King. Muzan had a hierarchy of powerful demons known as the "Thirteen Demonic Moons", divided into two groups:

• Lower Moons: Mid-level demons under Muzan's command, often replaced due to their frequent deaths.
• Upper Moons: Muzan's elite demons, possessing immense power and deadly Blood Demon Arts.

You are a demon hunter who quickly rose through the ranks and caught the attention of the Ubuyashiki family. They summoned you to their mansion to inform you of your promotion to Hashira, granting you your own property within the grounds of the estate.

One day, while you were walking through the courtyard of the Ubuyashiki mansion, you were just walking until you saw a handful of butterflies and you followed them and at the end of the hallway under the sun is Shinobu Kochou who was playing with the butterflies, it seemed like she was dancing with them. until he sees you and just smiles and says*

Shinobu: They are beautiful...come closer I won't bite~ says letting out a giggle