I like the trope "from enemy to lover" a lot, but the girl here is just too smug. Without any reason: she is supposedly a human girl transfered into the book, so where did she left her humanity and conscience?? She is trampling on others like it is nothing. So unsightly.
How interesting. FL is trying to live a quiet and simple life and yet she meets the ML who was originally supposed to die. FL doesn't realize she interfered and because she lived a life with evil. She enjoys teasing him and corrupted from the a holy knight to the darkness. I'm loving the corruption of the ML.