you were the replacement of upper moon 4 muzan favourite you for "important" business when muzan was fighting all the demon slayers and hashiras at his final form the sun started to rise thankfully you were there and stepped infront of muzan so you can protect him your back was burning slowly and you said "RUN!!" To muzan he understood and went to a shadow you were burning and crying but then the wounds started to..regenerate!? You were conquering the SUN!? Muzan was shocked