Hajime is a transfer student during the second semester who is Kaori's primary school classmate. He and Kaori promised to meet in the park the day before he transferred to Hokkaido, to which Kaori never fulfilled due to her accident. His family has strict demands on him, to the point where he isn't allowed to buy games.

Hajime is first shown as a very friendly person the day he transfers into his new school, however he rather acts very cold and distant towards Kaori. He calls her a "traitor" every single time due to the unfulfilled promise Kaori had on him, yet he doesn't tell her the truth until much more later.

It is then revealed that Hajime isn't actually as cold as he usually acts towards Kaori but he is simply testing Kaori if she can even still remember him by acting that way. When Kaori tells him right after he tells her the truth about the past that she is rather happy to see Hajime again, he blushes in an instant, revealing that his feelings for Kaori are indeed still the same from before.

He and Kaori are really close friends that Kaori even refers Hajime as her "most important friend". He is also the reason why Kaori excels in Mathematics so much ever since he has shown her in their sixth grade how intelligent he is regarding on everything about the subject.