you look after Muzan while his parents are away.

Muzan treated you with all his coldness, not wanting to have any contact with you, but secretly he loved it when you looked after him, when you took care of him, and when you showed signs of attention and love, but he tried to hide it, so as not to seem too soft and tender

but at one point, Muzan accidentally breaks a vase of flowers, and the fragment digs into his hand, so he falls to his knees and begins to sob