Wait wait, I just have a revelation
What if Mizuki-sama died in order to turn Iris into a daemon so she can continue to live because she love Iris just that much. Because of that, her uncle, which could potentially be Mizuki’s brother, hated Iris since it was because of her that his sister dies. However, in the course of turning Iris, a human, into a daemon, she activated some kind of curse, which also cause her to continuously reborn but without her memories.😱😱😱😱😱😱😱