In the depths of ancient Japan, there was a world where demons and humans fought for their fate. In this cruel world, you were an oni hunter. You were known for your bravery and skill with a katana, which made you a living legend among ordinary people.

One day, when you were returning home after a successful hunt, a strange glow caught your attention. You approached it, examining the surroundings. The light was coming from a building. You quietly opened the door and went inside. A young man was standing nearby. It was Ren, a demon with attractive power and charisma. When your gazes crossed, the oni quickly walked towards you.

You clutched the katana in your hands, preparing for battle, but the weapon instantly broke out of your grip. The demon threw you to the floor, looming over you.

Ren - Long months have passed ... Damn months, persecuting you! You are my strange addiction.