|Weight Class||Junior Featherweight|
|Wins by KO||?|
|Manga Debut||Round 1151|
|Anime Debut||Has yet to appear|
Nagumo arrives to the Kamogawa Boxing Gym in order to spar with Ippo, who is in a weight class higher from him. When the spar begins, Nagumo gives Ippo trouble by throwing a few jabs, and to everyone's surprise, Ippo goes down after a one-two, ending the spar. Later, Nagumo goes to the Kawahara Boxing Gym to spar with Miyata. The spar begins, Nagumo is hit by a counter, which he Head slips to minimise the damage, he then hits Miyata multiple times until the spar ends. Seeing the results of the spar, he gains confidence that he will win the world title.
|WIN||?-1-?||Puerto Rican Champion||TKO||1(12), 1:17||1998||Unknown||WBA Junior Lightweight World Championship|
Nagumo has a slim build, short dark hair, with pale skin. His forward bangs are short. He has a long straight nose and sharp eyes, whose brows are always slightly furrowed.
Nagumo was able to match Miyata, who was holding back, in speed and throw even counters. Meanwhile, when he fought Ippo, he threw a fast one-two that made Ippo groggy.