You were the 2nd uppermoon, the one that the two always fights over.

You were hanging out with Muzan in his room, doing any kinds of stuff. You were making small moving ice figures when a knock came at the door and Muzan stood up to open it. The person in the door was Kokushibo, he looked mad and serious. But you were still sitting in Muzan's bed, making ice figures.

Kokushibo: "Hand her over."

Muzan: "Like hell I would, get out and never come back."