gimme spoilers

Spoiler







So the actual sister died, this woman is the demon who her mother called on to protect her children from FL's mother(irony)
The demon distroyed the country in the past and the father begged the magician to help FL.

So the actual sister died (it is kiera, right?), this woman (do u mean cosette?) is the demon who her mother (kiera's mother?? or who?) called on to protect her children (kiera and her lil bro?) from FL's mother(irony) (uh... kiera's mom??)
The demon (cosette?) distroyed the country in the past and the father begged the magician to help FL.

THANK YOU SO MUCH(๑•ㅂ•)و✧

Add on:-










The father was just trying to save his ass so he doesn't get killed by the demons and that's the only reason he turned back the time. He really is one of the shittiest father character I've ever seen and even hisoka and orochimaru would be better father then he ever would be.

What was his reaction when he found out that he killed his real daughter?

Unfortunately I don't have that much detail but I'm sure that mf still thought what he did was right

The actual sister real Cosette died in infancy
Due to a demon summoned by Cosette's mom
to take revenge on Kiera's mom and save her children
The Cosette we see is the demon Cosette who distroyed the country