Lucy has strong emotions of hatred and vengeance towards regular humans mainly because of how she was treated by the majority of them as a child, making fun of her horns and giving her insulting names.
Nyuu is a split personality of Lucy that developed after a bullet hit her helmet encasing her head. Nyu has a childlike personality and infantile knowledge of the world, forgetting even that she is a Diclonius and how to use or manifest her vectors, leaving her as a human with horns.
Poll