When she was a kid a man would often come to her parent's house, he saw her siblings and he would feel bad. He begged the parent's to stop hitting them but it never worked so instead the man convinced the parent's to at least sell one of them. He prayed for the one to finally get a better home

That man died he was your brother after he died you became a demon slayer. You were at the butterfly mansion to get a checkup from Shinobu then suddenly you were hugged by a girl

"It's...you!"