Emily Jane Pitchiner/Mother Nature

Emily has always been important to Pitch. She is a lot like him actually. She loses it when she thinks he abandon her but it's really just one huge misunderstanding. So she learns some powers and goes a little crazier. She mets Sandy and the two eventually become friends and end up on Earth but they are seperated. Emily becomes Mother Nature. And when Pitch takes Katherine and plans to make her a Nightmare Princess, Emily will have none of it. Pitch already has a daughter! She goes to tell him, she will even stay out of his business but if he touches Katherine, it's over. So Pitch agrees that Emily will be his only daughter and then traps Katherine into a world of Nightmares. Work arounds. Even though he is the Nightmare King, he still loves his daughter very much. A weakness of his.

Katherine

Katherine isn't actually his daughter but he did have plans to make her one. He terroized her for months about it. Though because of his daugther, Emily (Mother Nature by now) told him to knock it off. He did but he then trapped Katherine into a world of nightmares. Pitch cause her a lot of heart ache. I think Katherine might be Mother Goose.