Nekomaru is a vigorous, boisterous, openhearted student who is passionate about supporting athletes, but suffers from dyspepsia. He frequently shouts when speaking, being a team manager. He is very optimistic and his willpower is immeasurable, but he isn't very smart and he's very bad at lying. He also really appears to enjoy fighting, often in the form of very serious training.

Nekomaru sees no shame in talking about certain things that could make others feel embarrassed or uncomfortable. For example, he never misses a chance to loudly proclaim when he needs to go to the restroom. He also tends to get too close to other people's personal space, though he does this just to check their potential as athletes. Furthermore, as the self-proclaimed Ultimate Masseur, he frequently offers his special massage to the others to the point that he forces them to receive his massage, as shown in his first and fifth Free Time Events with Hajime. He states that his massage is his own ultimate weapon that can relieve fatigue in an instant, but it also appears to be highly addictive to the receiver.

Though Nekomaru may appear scary and aggressive, he has a very kind heart. He cries quite easily and isn't afraid to show it. As a team manager, he can be quite strict, but he is very supportive and inspiring to his athletes and strives to improve them however he can. Teamwork and fighting spirit are very important to him.