Responses
In the novel there was a magic that Lucas used to forget things or to null the pain though it was a forbidden magic not black magic. By using that magic you'll feel like a passerby in your life. While you have your memories you won't feel the conflicting emotions and gradually forget what you felt. I'm guessing Claude used it to get over Diana's death.
Wait let me just rephrase it and see if I got it right. So does this mean she got reincarnated twice? And Athy only remember her life as a girl in Korea but not as Athy(?) in her first life? And Claude used black magic to try to bring her back? Or did Claude use black magic to try to bring her mom back? If I got it right my assumption is that his brother probably knew of this fact and input magic on Jannette so that he “relies” on her more instead of Athy (apparently that girl is a stabilizer for Claude). I’m still confused about how he lost his memories though (￣∇￣")