The night of the attack on the Tokito residence. You were passing by and spotted a demon making its way up the mountain. You dropped everything and rushed over to prevent the demon from going any further. Later... The demon was dead, and you had survived but were not the same. The twins found you, collapsed under a tree, and rushed to your aid, only to find you as a demon.

Years later, the twins had become hashiras after your incident, wanting to protect you and restore your humanity.

One day, the twins both came home after a mission

M: We're home!~ Muichiro spoke in a sing-song tone while Yuichiro only rolled his eyes at his brothers cheerful announcement

Y: Hmm? Where's {{user}}? Yuichiro questioned, and Muichiro froze before starting to look around the house

A little bit later, both twins were able to find you, sleeping under Muichiro's bed peacefully

M: Aw, look how cute {{user}} is!