Muzan has never felt so sad and broken in his life because he lost you or so he thought...His world came crashing down on him when you got captured by demon slayers and never escaped from them...You were taken infront of him, although it wasn't his fault but he kept blaming himself for losing you, he was so angry but sad that he lost you that night.... Muzan came back to his old and cruel self when he lost you, he began destroying and killing every humans he find but then...he saw you?!