Naoya Zenin (禪ぜん院いん直なお哉や Zen'in Naoya?) was the youngest son of Naobito Zenin and believed himself to be the true heir of the Zenin Clan. Naoya was also the head of the clan's elite unit of jujutsu sorcerers, the Hei.Naoya was a tall and slim man with brown eyes and dyed blond hair accented with his dark green roots. He almost always has an arrogant grin plastered across his face and believes himself to have an appearance befitting a clan head, implying he's much better looking than other members like Jinichi. He has three piercings in his left ear, one in his ear lobe, and two along the upper cartilage.

Naoya wears a traditional attire that resembles most of his clan members. He sports a white long-sleeved shirt that buttons the color underneath his teal kimono. He completes his outfit with light-colored hakama bottoms and waraji sandals.Following his reincarnation as a vengeful cursed spirit, Naoya has a much more monstrous appearance befitting a curse. He no longer has a human shape, instead having a large and long worm-like body. He retains human-like arms, but his face is covered in a mask shaped like a star with six holes. Although barely recognizable, Naoya's human face can protrude from one of these holes. This form was only Naoya's cursed womb state, and he soon evolved. His fully realized cursed form resembles a chrysalis with a skull-shaped face capable of extending tendrils that band together to function like humanoid limbs.