As mentioned previously, Kristoff was adopted by a family of trolls who are also conveniently love experts. Handy. Since the age-old fairy tale of Cinderella, most people have an idea that step parents simply arent nice people: they are jealous, petulant, sometimes malevolent sorceresses... And although it is true for some - aside from the whole witch thing - Frozen has shown rather beautifully that trolls can be more human than humans.