Kayo Tomiyama is the neighbour of the protagonist and a former fashion designer. A cognitive manifestation of Kayo as a phantom idol was created by Merope from Nagisa Kamishiro’s cognition, also known under the codename Okyann. It's revealed that she knew Nagisa and his family when he was a lot younger, and is currently a full-time housewife. She quit her job as a fashion designer after having kids, but in her social link, it's shown that when she was younger, Kayo dressed in 'gyaru' fashion, which is how she ended up meeting her soon-to-be husband. She wishes to connect more with the younger generation.

Voice Description: Medium-female vocal range. Extremely kind and caring, but still maintains a slight amount of playful energy from when she was a more rebellious youth, and is truly fascinated with her husband.