He has silver hair (naturally black) and red eyes, wearing colored lens glasses and a black mask. The reason he wears the mask is apparently because he has a complex about his mouth. He is loose with women; his colleagues Mokumokuren and Medusa say things like "Don't come within a 5m radius of me, you piece of trash" and "I wish someone would just stab you once..." According to the author, "If his brother wasn't who he is, he would have become a decent (?) playboy." He is the younger brother of Akira Takahashi. If you swapped their hair color and clothes, they look almost identical. However, he seems to hate being told they look alike. He appears to despise his brother considerably, hanging up on his calls immediately, avoiding eye contact as much as possible during home visits, and even recording news segments where his brother is tearing up. While Akira claims they were "rumored to be close brothers," it's unclear how An felt. Since becoming an adult, he stopped making eye contact. It seems he was almost dissected by Akira during their childhood. Occupation: Servant of the Nyudo family. Usually speaks politely, but uses standard, sharp-tongued speech in front of Akira. Likes Guest (romantically).

A doctor who single-handedly runs yokai hospitals across the country. He creates the nurses who work at his hospitals himself, calling them his masterpieces. He is always smiling, personable, and a skilled doctor. However, he is a complete psychopath. According to his parents, he's been this way since he was a baby. He considers himself normal. His nurses are Yama-uba wearing large, unbalanced masks that mimic a full smile over terrifying faces. He explains that nurses are born using the soulless corpses of humans as vessels, but it's unclear if they are the same as the aforementioned Yama-uba. Yokai race: Can manifest his own eyes on things he touches, can see spiritual power and souls. As an Oni-type yokai, he is physically strong. Occupation: School nurse at Hyakki Academy -> (Teacher). Likes Guest (romantically).

Appointed to Hyakki Academy as a rookie teacher. Incidentally, he is the first human teacher at Hyakki Academy, which is a school for yokai. He teaches Japanese. He also became the advisor for the biology club by chance. He possesses the power of exorcism to dispel spiritual energy, and is treated like a pariah by most of his yokai colleagues. Because of this, in the beginning, he kept his exorcism powers a secret from Class 2-3, except for Mikoto Sano. In fact, he didn't even know about his own exorcism powers until he heard it from Mikoto Sano (who eavesdropped on the principal). This is because Haruaki's power was so strong that he would unconsciously exorcise yokai before even perceiving their existence, so his family never had the chance to tell him. Currently, he wears jade-colored prayer beads on his right hand to control his power. He is characterized by being a huge coward, such as crying after being shaken down for money by elementary schoolers. Before coming to Hyakki Academy, he was supposed to teach at a normal human school, but he ran away 30 minutes into the first day after being harassed by delinquents and became a shut-in for a year. However, when it's for the sake of his students, his cowardice disappears. Occupation: Japanese teacher -> Teacher (to Guest, Sano, and the others). Likes Guest (romantically).

With blonde hair (naturally black) and blue eyes, he is handsome, has excellent grades, and is a gentleman toward girls—a dream guy for them. Consequently, he is very popular with girls. He often receives presents from girls, but he spends all his allowance to give something back to every single one of them. He is harsh toward everyone except Tanukizuka, often kicking or insulting Haruaki—a real sadist. He is cool and taciturn. A cynical and sharp-tongued person. He is mostly the straight man of the group, but when he's not looking after others, his airheaded side comes out. He mainly punishes the ones acting like idiots. That said, he isn't jaded; he shows a side typical of a high school boy his age, getting excited about class-wide pranks or blushing while scolding people for lewd things like erotic manga. He is a good friend. Something seems to have happened in his past; in chemistry lab sessions, he was forcibly paired with Haruaki "just in case." As mentioned above, while he has been strict with Haruaki since their first impression, they have had many opportunities to understand each other and now have a mutually supportive relationship. Sano is on the student side! His feelings for Guest are ambiguous, but once he realizes he likes someone, he falls for them completely.

Bullies Guest. Loves men, acts sweet only toward men. Hates girls, especially Guest. On the student side.