Voiced by: Akari Kitou (Japanese), Lizzie Freeman (English)A young-looking college student. When she was 11 years-old she was kidnapped for 2 weeks by a group of Yokai, who pleaded for her to become their "Goddess of Wisdom" to give them guidance and make peace among them. She agreed, and in exchange she lost her right eye and left leg. Since then Yokai have crossed the country to ask for her help as a mediator.
- Action Girl: When Kotoko needs to fight, she'll do it with no hesitation.
- An Arm and a Leg: In exchange for becoming a Goddess of Wisdom for Yokai, she lost her right leg and left eye. She wears now wears a prosthetic leg and uses a cane to move on her own.
- Casual Danger Dialogue: While still taking things seriously, he's fairly nonchalant in life threatening situations. For example, her reaction when Steel Nanase walking toward her? Comments on her big breasts.
- Classy Cane: She uses a customized cane to help her walk with her prosthetic leg. The tip of the cane is shaped like a cat curled up and sleeping. The manga/novel mentions that she can walk fine, but her family is concerned that the stress of moving around a lot with her prosthetic leg can cause it to fall down, which justifies the use of a cane.
- Clingy Jealous Girl: Kotoko gets pretty jealous of Saki when she and Kuro have a reunion after their breakup and attempts to assert herself as Kuro's only girlfriend.
- Deity of Human Origin: Subverted. Kotoko isn't actually a literal goddess, merely the chosen peacekeeper of the supernatural community.
- Experienced Protagonist: She's been the Goddess of Wisdom for six years at the start of the series.
- Eye Scream: As part of her deal with the Yokai. She wears a glass eye as a replacement.
- Handicapped Badass: She may have a prosthetic leg, but that doesn't stop her from trying to fight the Steel Nanase spirit.
- Likes Older Men: She's attracted to Kuro, who is a few years older than her.
- Nice Hat: A white beret with a black bow.
- Not So Above It All: For all her serious demenor, when it comes to Saki, Kotoko loves to screw with her from introducing herself as Kuro's new girlfriend, sending spirits to freak her out, and setting the ghost of a Dirty Kid on her.
- Older Than They Look: To anyone else, she looks like a 14 year old girl. Shes actually 17 when she first appears, and is 19 by the time the story starts in earnest. Kotoko is 20 after the end of the Nanase arc by a few months.
- Proper Lady: She dresses in fancy clothing and behaves in a professional manner.
- The Lad-ette: While she's a Proper Lady 95% of the time, when it comes to discussions about sex, she comes across as this, much to Kuro's chagrin.
- The Ojou: Kotoko is publicly known to be from an upper-class family and the supernatural community treat her as such. They address her as "My Lady" (English) or "Ojou-sama" (Japanese).
- Wise Beyond Their Years: Downplayed as she is 19, but she is certainly full of wisdom and knowledge after becoming a Goddess of Wisdom.
- Zettai Ryouiki: Kotoko wears these to complement her fancy doll-like clothes.
Voiced by: Mamoru Miyano (Japanese), Brandon Winckler (English)A young college student who gained immortality from eating yokai flesh when he was 11.
- The Dreaded: To any Yokai he comes across, who genuinely see him as an insidious monster.
- Feels No Pain: Kotoko took note of this when he willingly let his arm be devoured by a rabid yokai. Thanks to his condition, Kuro has developed a complete disregard for pain and self-preservation.
- Good Thing You Can Heal: Kuro can regenerate from pretty much any injury.
- Has a Type: Tall, mature dark-haired women who are older than he is.
- Humanoid Abomination: Most yokai perceive Kuro as horrifying monster that should be avoided at all cost.
- Perpetual Frowner: His default expression is always frowning. This is mostly likely caused by the trauma he experienced in his childhood, although there are times where he does genuinely show a smile.
- Poisonous Person: His blood is revealed to be toxic towards yokai, which is why they avoid him most of the time.
- She Is Not My Girlfriend: While Kuro and Kotoko are "officially" a couple, he still denies having anything to do with her, which always makes her mad and clingy to him.
- Weak, but Skilled: Kuro doesn't exactly know any martial arts and isn't the strongest person, but he does know how to play safe in a fight and wait for an opportunity to counter.
- Winds of Destiny, Change: Whenever he temporarily dies and resurrects, he can see many possible futures and choose which one happens.
Makurazaka Police Station
Voiced by: Misato Fukuen (Japanese), Lauren Landa (English)A police officer and Kuro's ex-girlfriend.
- Action Girl: Saki tried to take on Steel Lady Nanase, but her fists went through her.
- Dope Slap: She does this to Kotoko when she brags about being Kuro's current girlfriend.
- Due to the Dead: At the end of the Steel Lady Nanase arc, Saki pays tribute to Terada at the deserted gas station where he was killed, knowing that the Tokyo Metropolitan Police will shut the case and blame his death on a killer who's not arrested since they can't handle supernatural crimes.
- Nervous Wreck: She's normally calm and thoughtful, but because of her encounter with a kappa yokai while walking with Kuro, she gets easily scared of yokai whenever they appear. It doesn't help when yokai always appear with Kotoko whenever she visits.
- Nice Girl: Even after Saki called off her relationship with Kuro, she was still nice enough to ask him how he's doing and doesn't blame him (or his heritage) for the PTSD she experienced. With Kotoko on the other hand, it's 50:50 with majority of the time wanting to punch the girl for harassing her.
- Only Sane Woman: She's the only one who questions everything about yokai activity. It makes sense since she's the only normal one in the group and that any other person in her position would probably fear yokai too.
- The Team Normal: Saki's the only one who doesn't have any special abilities like Kotoko and Kuro, but she is physically fit and athletic.
Voiced by: Mayumi Sako (Japanese), Cristina Vee (English)
Kuro's older cousin, whom he regularly visits at the hospital.
- Big Bad: The one who is really behind the Steel Lady Nanase incident.
- Color Contrast: Her red and black attire acts as a contrast to Kotoko' white and blue when being shown next to eachother.
- Cop Killer: Rikka's indirectly responsible for killing Terada through her specter proxy.
- Evil Counterpart:
- She has the same powers as Kuro, due to also having eaten Yokai flesh.
- Like Kotoko, she is a patient from the same hospital with abnormalities and use brains and stratagy.
- I Just Want to Be Normal: Her ultimate goal is to create a being that can reverse the effects of the Mermaid and Kudan flesh on her.
- Ill Girl: Is constantly in the hospital.
- Myth Arc: The series centers later (after the Steel Lady Nanase arc) to stop her from doing anything to harm human society by using the paranormal.
A murderous yokai that resembles deceased idol Nanase Karin.
- Art Initiates Life: She was created in the image of a painting of Nanase Karin that Rikka made.
- The Blank: She just has an empty black void where her face should be.
- Clap Your Hands If You Believe: She's a yokai created by people's belief in her, and only exists as long as people believe she does.
- Gag Boobs: Her large breasts are often commented on.
- The Heavy: She's the villain who does all the fighting, while Rikka just manipulates events from behind the scenes.