Shinoda
Shinoda took over as the chief trainer for Aoki Masaru, Kimura Tatsuya, and Itagaki Manabu, keeping Coach Kamogawa's legacy of brutal, no-nonsense training alive. His fighters have actually called him "The mud-fighter producing trainer from hell"—which says something about his methods.
He's not the flashiest character around, but Shinoda clearly knows boxing. He's got a solid eye for what works in the ring. He's also known for coming up with the motivational catchphrase Gattsu de Gattsun Gattsun da!, which has become pretty iconic among fans.
Content compiled by AnimeList.moe from publicly available sources.