Keep reading. It won't be long before you know. But if you must
FL technically "dies" or rather goes to the spirit world or smth, gets trained by two Spirits and returns OP. Her hair and eyes represent the two Spirits. FL returns in her own body, 1 year or so later in the normal world where everyone assumed she was dead. But there's no misunderstandings or anything, ML and other friends see FL as soon as she exits the spirit world and recognize her.

Still in early chapter, i don't mind spoiler
Why is the FL hair in cover is white, meanwhile in manhwa orange? Did she die and reincarnate?