User blog comment:TheJudicialDoll/New Mothy Song - "White Brick and Black Mourning Dress"/@comment-50.88.50.254-20150106054142

What I think is that the song takes place possibly sometime after EC 1000. The hand mirror is one of the Four Mirrors and that the boy is Allen or possibly MotHeavenlyY, since in order to be with him she has to be pure. Not sure who the girl could be though...