I am in confusion. Help

It is kinda of confusing…the OG soul of his daughter I believe was the one that endured the suffering of experimentation from the mad scientist and at some point made a deal with a void demon for time reversal and her pain to end…I think when she died the FL’s soul entered her body to complete the curse. So, biologically she’s the duke’s daughter but he recognizes that the odds of having his child back exactly as she was when she was kidnapped as a baby were slim to none…he’s just happy that he’s gotten to know the soul currently occupying his daughter’s body and remembers his OG daughter as well…that’s my guess at least… ╮(￣▽￣)╭

But isn't her memories of her past life too solid? I'd imagine that the mad scientist who was experimenting on the OG daughter caused the fl soul to enter. But I can't believe the OG daughter soul is dead. Maybe they fused or something or a classic plot of completing one life in the modern world in-between lives.
Because as I understand the plot the void demon takes 1 part of her per life and repeats until she's fully consumed. We can see that the demon already have her eyes and her green magic. But we only remember 1 life.

You may be right about a fusion of the 2 souls that’s a possibility. From my understanding the soul currently occupying the body had lived multiple lives, but the one she could remember the most clearly was her original one in Korea which I think Salem (beautiful, white haired boy who has the same ancient curse as her) said it’s rare for people to remember anything about their past lives. I think that she has the OG daughter’s memories since she’s in her body but that her soul has passed on, I had thought the void demon assigned to her body had stolen the powers of green from the OG daughter along with a portion of her eyes as apart of the pact…you could be right though…I’m not sure about any of my reasonings. (⌒▽⌒)