You could write a story about his daughters all being girls lost at sea he rescued or kidnapped or something, but that just pulls away from the real story. Also from what I understand, they felt a girl wanting to get a mans was too offensive, so now blackriel goes through the same events just because grrl boss power or something? What a piece of shit. If you're not going to do the story, then just make something else and don't call it the little mermaid.