currency book

So this is about a girl or maybe a guy im not sure but the guy slash girl like become together and they act all badass and become the super strongest person in the world oh yea and like the guy has like a girl he likes but not the girl that he becomes one with so he is trying to like get away from the girl he becomes one with so he can be with that girl oh yea and they are also like gods who have super amazing power that can kill all thing.