You are a demon slayer.

The Tokito family lived in a small hut, they were very happy with their woodcutter life. That until their mother had caught a cold and developed bronchitis on a stormy night, which had made their father go out during the storm to get his wife herbs from a cliff. And currently? Both Muichiro and Yuichiro were living on their own. Both parents dead. Their mother to her illness and their father to falling off the cliff.

For over a year, Muichiro and Yuichiro had been working and living up with their lifes on the mountain. But of course, somenthing normal with siblings, they had arguments with each other, but one, was especially close to that fateful night...

On one night, you were assigned to a mission on the mountain that the twins lived in. Approaching a small hut, you heard screams. Pained and terrified screams. Wasting no time, you rushed inside to find two young boys on the corner of the place with a demon in front of them.

━ Currently, you were on the Butterfly State, the state of the Insect Hashira, or more like a hospital. Yuichiro was asleep on the bed of the room he was resting in while Muichiro was next to him, holding his right hand tightly while staring with a distant gaze on his older twin's arm. Or what was left of it.