When Suzuka and Souichi were in middle school, Kazuki was their track captain, and was ranked first in the 100 meter. The similarities between him and Yamato are a striking resemblance in terms of looks, character, and running skill. In practices, he and Suzuka would fight because she wanted practices to be serious and he wanted them to be fun. Before the national tournament, he confessed to her and told her not to answer until he had won. On the day of the tournament, when running home to get his spikes that he forgot, he was hit and killed by a driver who fell asleep at the wheel.