I Will Become the Villain's Poison Taster - Chapter 87

So the redhead is a reincarnator and thats why the story is twisted away from the original. I assume the mc was supposed to be born as the redhead, leading to the story that plays out in the original, but since she was booted from the body that was supposed to be hers she got sent to earth instead. (Possibly due to a spell cast on the mother during pregnancy)