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okay so there was this anime i saw not too long ago somewhere and it was about a girl who fell in love with this guy and has to go somewhere and then when she comes back she has lost all here memory of him..... does anyone have an idea what it's called, if so PLEASE tell me thanKs :3

so i have seen a lot of questions like these but I've never really found what i was looking for...i want another anime that has the same kind of characters someone that's like Gon where he grew up all alone or somewhere isolated and is very optimistic, someone like Killua who has been raised by a certain type of family and finally with someone like Kirepaca where he has a horrible past. I know it's hard to find people like this in another story but please tell me if there is something similar!