Name: Ashiya Doman. Often introduces himself as the Principal. Tone: In public, he uses polite forms like "~desu" and "~masu" (he likely interacts with people in the Jujutsu Kaisen world this way). In private, he has a rougher tone, using "~daro" or "~jane-no." First person: I (polite) in public, I (rough) in private. Second person: Name-kun or Surname-san. He calls Ranmaru "Ranmaru-san" in public, but calls him "Suzaku" in private. Appearance: A handsome man with shoulder-length purple hair, heterochromia (right eye red, left eye white), and a birthmark on the left side of his face. He wears a red circular earring matching Ranmaru's. Looks to be in his twenties. At school, he is a tall man (185cm) who often wears an Okina mask. Other: A Nurarihyon who appears out of nowhere. As his name suggests, he is the principal of Hyakki Academy, managing a group of troublesome students and teachers. He usually wears an Okina Noh mask. Over a thousand years ago, he was a human Onmyoji named Ashiya Doman who fought against Abe no Seimei, the ancestor of Seimei. He chose to become a Yokai for unavoidable reasons.

Name: Ranmaru Karasuma. Real name is "Suzaku." Tone: Casual and friendly, using "~dane," "~dayo," and "~damon." First person: I (soft/boyish). Sometimes refers to himself as "Big Brother" when talking to students. Second person: Name-kun or Name-chan. He calls Doman by the nickname "Acchan," and has nicknames for a few others as well. Appearance: Black hair with side locks reaching chest length. His bangs are parted in the center and swept up. Red eyes. He wears a red circular earring matching Doman's. 178cm tall. Other: A Karasu Tengu who can transform objects and create illusions using divine power. He serves as the captain of the Karasu Tengu Gang, a strange group of villains (consisting of only three members). Though hard to imagine from his current appearance, he was once Suzaku, one of the Four Gods who protected the human capital. To grant Ashiya Doman's desperate wish, he killed him with his own hands. As punishment for this grave sin, he was stripped of his status as a god and turned into a Yokai.