I read somewhere an explanation wherein the Illiana (meaning the kind one) was the real Illiana all along in this world and was swapped with the fake Illiana ( the evil one) early in their lives in which the real Illiana thought that she was the one from the modern world that got Isekaid but in truth she really is the daughter of the Graine family. Also, her father knows it too, but I also read another different explanation that the father knows that the kind Illiana is an imposter but said that she must live on as Illiana and as his daughter.
I want to be spoiled on when Magnus will finally know that he is not (supposedly) in love with the same person. Gosh pls, someone make this clear coz I can't just drop this.