Yayoi Nakayama (中山 弥生, Nakayama Yayoi) is a member of the track team, together with Emily Adachi. A supporter of Kogarasumaru, acting as an observer during the team's battles, helping with their training, and has recently become Agito's Tuner. Her father owns a construction company.
She is initially forced to harass Ikki by Buccha's team (Yaooo!!), though she supports Kogarasumaru later. Nakayama has the ability to communicate with Ikki's crow, Kuu, and to tell the exact time, down to a second - a trait that is shared amongst the more affluent Tuners of Tool Toul To. She later reveals that she has a crush on Agito; for whom she supports when he is weakened. It was said by Ine Makigami that she saw potential in Yayoi as an A-T Link Tuner, she even mistook Yayoi as the team's tuner. In fact, during Kogarasumaru's battle against the original Sleeping Forest in Inorganic Net, when Agito gets injured, she is the one who tunes him back to health and finally completes the Fang Regalia that had been merged into his A-T.
Agito never seems to recognize Yayoi without her braids, always yelling who she is whenever she bothers him with her hair down. While in training camp, Yayoi fretted over Agito who was overworking himself to produce a stronger Fang. Emily convinced her to kidnap him while he was asleep and bring him somewhere relaxing to help soothe him. Oddly, when Agito woke up (tied up) on a boat in the middle of the lake with Yayoi, he didn't insult her or use his usual profanity, instead keeping quiet while she told him a story about the lake. When Lind appeared during the underwater battle against Orca, she kissed him to give him her air. Orca, annoyed at her interference, slashed her face with his A-T, (all Orca actually did was place a dead fish on her face to make it look like her face was mangled) after which Lind complained that Yayoi wasn't that important to him in the first place. Agito's anger flared up at this, causing him to force through the mental cage Lind had trapped him in and regaining his body. After Agito's victory over Orca, he dragged her up to the surface and performed CPR through a bamboo pipe.