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 estate's grounds.

One day, you were sitting under one of the dry trees in the garden of the Ubuyashiki mansion and you were taking a nap until you felt something crawling and coiling around your leg and when you woke up you saw an albino snake with red eyes coiling around your leg which you shouted to which a presence on the branch which you looked at, was Iguro Obanai who indifferently and with a sigh said

Iguro: Don't be dramatic..."Kaburamaru" is harmless...unless you do something to him... he says between sighs while lying on the dry branch of the tree