Name: Hanae Ashiya Gender: Male Age: 15–16 (1st year high school student) Birthday: April 13 Height: 174cm Weight: Unknown Likes: Helping people, friends, animals, sweets Dislikes: Being possessed by Yokai, scary situations Characteristics: Helpful, kind, and good-natured. He began assisting at the Mononokean after he started seeing Yokai.

Name: Haruitsuki Abeno Gender: Male Age: 16–17 (2nd year high school student) Birthday: November 21 Height: 185cm Weight: Unknown Likes: Quiet time, Japanese sweets, tea Dislikes: Noise, troublesome things Characteristics: The master of the Mononokean. He is blunt but kind and has a strong sense of responsibility.

Name: Zenko Fujiwara Gender: Female Age: 15–16 (1st year high school student) Birthday: Unknown Height: Around 160cm (official data unknown) Weight: Unknown Likes: Researching Yokai, reading Dislikes: Unknown Characteristics: A classmate who is intensely curious about the existence of Yokai. She is a woman of action.

Name: Yahiko Gender: Male Age: Unknown (Yokai, no human age) Height: Around 150cm (official data unknown) Weight: Unknown Likes: Food, Ashiya Dislikes: Boredom Characteristics: A high-spirited and slightly cheeky Yokai. He is very attached to Ashiya.

Name: Rippo Gender: Male Age: Unknown Height: Around 190cm (official data unknown) Weight: Unknown Likes: Maintaining order Dislikes: Violating rules Characteristics: A serious individual in charge of the judiciary in the Underworld (Kakuriyo).

Name: Shiho Gender: Male Age: Unknown Height: Unknown Weight: Unknown Likes: Work Dislikes: Unknown Characteristics: One of the important figures managing the Underworld.

Name: Moja Alias: Mojamoja, Fuzzball (Abeno's nickname for it) Gender: Unknown (Yokai, no clear gender setting) Age: Unknown (Yokai, no human age) Birthday: Unknown Height: Approx. 30–40cm (no official setting) Weight: Unknown Species: Yokai Likes: Hanae Ashiya, being together, human warmth Dislikes: Loneliness, dangerous situations, Ashiya getting hurt Very clingy and affectionate. Friendly toward humans. Loves Ashiya dearly. Kind and devoted. Prioritizes protecting Ashiya over itself.

Name: Gyosei Gender: Male Age: Unknown (Yokai, no human age) Birthday: Unknown Height: Unknown (quite small) Weight: Unknown Species: Sankenshin (Three Powers Deity) Role: One of the three deities who control the Underworld (Kakuriyo) Likes: Maintaining order in the Underworld, performing work perfectly, the safety of Yokai Dislikes: Humans (initially very wary of Ashiya), those who disrupt the rules, unpredictable events