Nathaniel Kurtzberg

Nathanaël is a student at Collège Françoise Dupont. In "The Evillustrator", after he drops his book revealing his art of Marinette, his crush, and gets made fun of by Chloé, he is infected with an akuma by Hawk Moth and becomes the Evillustrator, an artist supervillain whose drawings come to life.

Personality
Nathanaël is imaginative and artistic. He appears to be the quiet and shy type in class, and seems to be quite easily lost in his fantasies, initially shown to be daydreams of his (former?) crush, Marinette.

As the Evillustrator, he becomes more confident and direct, literally walking into Marinette's bedroom to ask her out and celebrate his birthday with him. Even akumatized, he seems to genuinely care for her, promising her to stop attacking Chloé and even defying Hawkmoth for a while for the sake of his date. He also seems to become quite short-tempered and reckless, as his response to Marinette tricking him was to yell that she was just like Chloé and trying to trap her and Cat Noir on a boat with a huge leak before taking off to continue attacking Chloé.

Marinette Dupain-Cheng
Nathanaël has a secret crush on Marinette, drawing comics in his sketchbook of him saving her from villains. When he becomes the Evillustrator, he has the confidence to act on his feelings, asking Marinette if she would go out on a date with him for his birthday. Her betrayal of leading Cat Noir to him hurts him deeply, and he angrily announces she is just like Chloé. It is unknown if Nathanaël still has romantic feelings for her.

With Ladybug, Nathanaël is relieved to know she is around to save the day. After his time as the Evillustrator, in his sketchbook, he draws a comic book cover that features Ladybug.

Chloé Bourgeois
Like most people, Nathanaël dislikes Chloé for being such a selfish jerk. He is horrified when she grabs his sketchbook from the floor, seeing his drawing of him and Marinette, and making fun of him for it. He also doesn't like it how Chloé bothers Marinette, so as Evillustrator, he draws a giant hairdryer to blow her away. At first promising Marinette that he wouldn't attack Chloé again, he changes his mind after Marinette breaks his heart and goes to destroy her.

Trivia

 * Nathanaël is very likely based on or named after Nathanaël Bronn, chief art director of the show.
 * In the French dubbed version of the show, the Evillustrator's name is Le Dessinateur, meaning "the illustrator," "the cartoonist," or "the designer."
 * The Evillustrator is one of the first supervillains that doesn't follow Hawk Moth's orders to get the Miraculous soon enough. As punishment, Hawk Moth briefly controls his body and almost prevents him from preparing for his date with Marinette.
 * He is left handed, as when he's the Evillustrator, his drawing pad is on his right arm and he draws with his left hand.
 * His shirt symbol is based on the french rock band Magma.