- Tsubomi Kido: Kano tends to tease Kido a lot and gets hit or kicked by her as a result most of the time, since she doesn't show any tolerance for it. Even though he gets called an "idiot" or "bastard" by her a lot, they seem to be very close childhood friends, seeing as they grew up in the orphanage together. In the fifth novel, Kido saw Kano waiting outside of the orphanage and gave him her scarf. He said that she appeared like a ghost, which made her cry. Kano describes her past self as "cute" and the two have called each other by their first names until the death of Ayano. He became extremely depressed when she had refused to talk to him for a week after a fight they had. When he was introducing the Mekakushi Dan, he called Kido in the manga, "the one with the death glare", he sometimes refers to her as "Danchou" or "leader". In the anime when Kano and Kido went to Takane's culture festival, he called her with her first name instead of her last name.
- Kousuke Seto: Seto grew up with Kano and Kido in the same orphanage, therefore they're childhood friends. When he was introducing Seto to Shintaro, he calls him a "giant frog". The fifth novel showed that they have had an extremely close relationship, especially as children. Both of them shared concern over Kido's disappearing acts and would go off and look for her together. Kano also stood up to Kido whenever she threatened to hurt Seto for his use of keigo (formal speaking), and the two would frequently talk to each other telepathically. They have called each other by their first names until the death of Ayano. Seto looked for Kano after he disappeared and showed empathy to Kano when he broke down crying in front of him. He then considers them brothers.
- Marry Kozakura: Kano is always teasing Marry whenever he gets a chance too. In the manga, Kano teases Marry with a job offer only to get frozen by her for a short period of time. Despite this, they seem to have a rather close relationship.
- Takane "Ene" Enomoto: Kano first meets Takane at the culture festival, together with Kido. The latter nearly beats Takane in the video game her class is offering as a challenge with a prize, losing by only 100 points, and Kano reveals that his friend cheated without the other noticing, and makes Kido apologize, later telling Takane that Kido has a "psychic ability".
In the fifth novel, it is revealed that Kano finds that her most prominent feature of all is her ability to be easily agitated, and that she really is spiteful and difficult to deal with. When Takane asks Kano (disguised as Ayano) if there is anyone she likes, she immediately takes it back, seeming extremely flustered and shy, causing Kano to think that she is stupid for getting that embarrassed over nothing.
While at the beginning, Kano seems either disinterested or annoyed by Takane's antics, he eventually ends up helping her find her real body, and comes clean to her about how he pretended to be his sister. At the end of the novel Takane teases Kano for posing as Ayano, and when she finds out that he is shy from Seto, her teasing increases, much to Kano's discomfort.
In the anime, Kano uses his ability to transform into Haruka to scare Takane.
- Ayano Tateyama: Ayano was told by her mother to be a "big sister" for Kido, Kano, and Seto. She was the one taking care of them in the orphanage. Ayano followed her wish and started to become friends with the three of them, which turned out to be difficult, as they thought of themselves as "monsters", due to their eye abilities. Eventually, Ayano came up with the plan to create a secret club of heroes and gave them their hoodies as a present. Ayano and Kano met before the three were adopted, and he appeared to be the most depressed when she died. When Ayano found out about her father's experiments on Takane and Haruka, Kano was the only person she spoke to about it. She asked him to use his ability and go to school as her while she investigated, to which he complied. When Ayano jumped off the roof, Kano couldn't stop her in time. In present-day, Kano describes her as a person who was really nice but very scary when being angry, mostly because Kano got scolded by her the most.
- Kenjirou Tateyama: The adoptive father of Kano, Kido and Seto. In the anime, Kano begged the snake to release Kenjirou, but without results.
- Ayaka Tateyama: The adoptive mother of Kano, Kido and Seto. Along with Kido and Seto, he was crying during the small funeral they held for her.
- Shintaro Kisaragi: When he met Shintaro during the hostage scene, he called him "interesting" and went along with his idea to free the hostages. He refers to him as "Shintaro-kun" and seems to tease him every now and then. In the third novel, he disguised himself as Momo and Ayano in front of Shintaro, making the latter starting to think that Kano might hate him. After Ayano killed herself, Shintaro met "Ayano", Kano in disguise, while walking home. When he scolded her about her usual lack of work ethics, Kano quietly retorted and brushed Shintaro aside. In present-day, Kano still thinks that Shintaro is kind of an insensitive idiot, but also a good person.
- Snake of Clearing Eyes: After Ayano's suicide, Kano threatened to kill it, but the Snake in return threatened to brutally murder his father, Kido, and Seto if Kano tried to interfere.
- Konoha: In Kagerou Daze IV, Kano helped Konoha to search for Hibiya and Hiyori, and referred to him as the Mekakushi Dan's "Combat Specialist". Kano became shocked when Konoha began to cry, after losing Hibiya again, but later on expressed interest in his eye ability.
- Haruka Kokonose: In the past, Kano actually met Haruka (in the guise of Ayano), and said that he was a really nice guy. It is most likely that Kano is aware of the link between Haruka and Konoha, and he did in fact witness Konoha being placed in the the tank in Kenjirou's laboratory. In the anime Kano made himself look like Haruka to torment Ene.