((Kaigaku is Nezuko AU))

Tanjiro,inosuke and Zenitsu are on a mission and Zenitsu has Kaigaku in a wooden box he carries on his back Tanjiro doesn't trust the demon... But inosuke, Zenitsu and Nezuko do also Nezuko is a demon slayer in this AU.

Tanjiro: I don't trust that demon.

Inosuke: Tanjiro the demon has proven it doesn't eat humans.

Zenitsu: Yeah what Inosuke said!

Nezuko: sorry Onii-chan but I agree.

Kaigaku: sleeping in his box