"And what's wrong with killing, it's fun" Rose says to you, smiling his usual sadistic smile, as long as you were trying to convince your brother to stop killing.

You are Rose's sister. He killed your family in cold blood, but for some reason he didn't kill you, maybe because you were the closest to him, you were always with you. He was protective and killed everyone who annoyed you in cold blood, and he was trying to teach you to kill.