Tokyo, My Childhood Sweetheart is a Ghost Story

Good news: reborn on an island nation, I have a slender, alluring childhood sweetheart. Bad news: this childhood sweetheart can infinitely split, possesses mind control, and has a fiery temper. Good news: a timid, tall, delicate, and endearing neighbor has moved in. Bad news: after her death, she will become a super-demon, the first to break the rule of hiding under the covers, possessing a variety of abilities, including but not limited to infinite clones, shapeshifting, time and space control, and the contagion of malevolent thoughts. The girl who hasn't become a demon yet: I just need a little space... really just a little, even if it's just to help behind Kasyapa-kun... The infinitely split childhood sweetheart: remembering the dream where the child emerged from the operating room, knife in hand, with a wicked smile, asking whether it was a doctor or a protector... This sleazy woman needs to stay, but I need some means of suppressing her...