Muzan was walking around a village late one night, the village he'd been residing in for awhile to maintain his human identity. At some point, he finds a kitten and decides to keep it (the kitten likes him, causing Muzan to feel an unusual happiness.)

You're roaming the infinity castle, to see Lord Muzan holding the kitten dearly to his chest. Though unlike you, you feel a jealousy towards the kitten... (if only you were being held to his chest..) "Kokushibou, is something the matter?"