Naomi (ナオミ) is one of Zatch's bullies in the park. Her biggest noticable feature is that she always grits her teeth.
Whenever she shows up, she almost instantly takes to bullying Zatch with whatever method she has at hand whether it be chasing him with her kiddie car or beating him to to a pulp with her fists while biting his head with her mamodo-sized mouth. Zatch is extremely frightened of Naomi because of her terrifying presence and because he cannot use spells to stop her it makes her all the more terrifying. Even though Naomi is always mean to Zatch, he genuinely cares about her, even attempting to save her from a lion at one point. Another of Naomi's noticeable attributes is her kiddie car. She drives a red toy car for one that has a picture of a man and a woman kissing on the front, which she dubs "Je t'aime-mobile" (ジュッデーム・モビール Juddēmu Mobīru). Naomi loves to mess around with Zatch, for example she once made him follow her as she bought things to bully him.
At one point while Zatch is trapped by Naomi he attempts to call to Kiyo to help him, but Kiyo shrugs it off and walks away leaving Zatch to be tortured by his cruel friend. A tall, strong looking man approaches who helps Zatch by scaring away Naomi. Shin, the strong man, is the first person to do anything to stop Naomi from bullying Zatch. This doesn't stop her forever though as she later comes back and bullies him relentlessly as always. However,this is also the first time Naomi is shown to open her mouth.
Kiyo may get some kind of cynical enjoyment out of seeing Naomi torture Zatch as in episode 28 while on their way to the amusement park, Naomi stops Zatch demanding that it is time for them to "finish their race". Their race, of course, consists of her chasing Zatch tormentingly with her toy car.
It's discovered in Episode 32 that Naomi lives in the same neighborhood as Kane, when he brings her to school to show her off to Shion, to top how Kiyo bringing Zatch to school interested her. Zatch becomes frightened and Naomi begins to attack him in her typical vicious ways as the rest of the class rumbles.
In episode 36 it is heavily implied that Naomi constantly bullies Zatch as a way to show that she really likes him.