Character Bios: Lucy/NyuLucy/Nyu: Nyu also called Lucy is the main character (Besides Kouta). She is a so called "diclonius" which explains her horns. But they contain a certain power (called "vector") which is similar in a way to telekinesis.
She has a split personality. One is the very friendly and childish Nyu, who can't even speak properly and the other one is Lucy, a cold-hearted killer who kills everyone with her special ability. But both characters have one thing in common despite all their differences: They are both in love with Kouta...
The difference between Nyu and Lucy:
Nyu is someone who does not use the vectors, would never purposely harm anyone, child like, doesn't know how to talk properly, has no idea what the word personal space means or many other words either, also she never wants to be parted with Kouta, most of the time wherever Kouta is Nyu is probably close behind somewhere...But Nyu is someone you could easily like, shes also the comedic personality in the show despite the fact that the word she really only says is "Nyu" or "Kouta"...Later around the show she begins to talk a little more...
Lucy is cold, murderous, hostile to anyone who tries to take Kouta away from her. (In Ep. 6 she used her vectors to punch Yuka who had gotten too close to Kouta) Though she has a soft side as well, the side when she's around Kouta, Kouta is the only person Lucy would never kill or do anything to harm, having already hurt him in the past. Her kinder side shows around episode 13 when Lucy tells Kouta the thing shes always meant to tell him...
Lucy is the kind of person who would kill you without a second thought, thats probably caused by the harsh past she's had. Though she won't kill Kouta ever, or Kouta's friends: Yuka, Mayu, or Nana. Although it was because of Lucy that Nana got her limbs replaced with artificial ones but Lucy has no real desire to kill Nana...