Kousuke Seto/Relationships

Mary
Seto first met Mary while wandering around the forest and stumbling upon her house, Mary was afraid that she would turn him into stone. However, he misunderstood what she meant and thought she was shy, and put his headphones on her to comfort her. He is Mary's closest friend.

Kano
Kano and Seto grew up in the same orphanage together and are childhood friends.

Kido
Kido and Seto grew up in the same orphanage together and are childhood friends.

Ayano

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, what 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