It begins with a girl with magic that was killing everyone in a house. I think the ML kills her. She was being controlled by some guy older than her that used her as a slave, she actually didn't want to kill anyone. After dying she wakes up as a child before everything bad happened and searches out the ML and his family so that theh can help her. I think she had red hair. That's all I know, I couldn't read much and then I couldn't find the novel. If anyone knows the name, thank you in advance.