Koga, also known as Koga the Kicker, is the youngest known member of Kisara's team. Unlike Ikki and Ukita, he seems to bear hateful grudges against Kenichi, who he plans to take down himself, and Miu, whom he calls "Neko Shojo" (Cat Girl). Though he is a strong fighter, he possesses a carefree attitude, which usually earns him a beating from Kisara. He is very loyal to Ragnarok and is always eager to deliver punishments to those who betray the gang. In the anime, he is much shorter than he is in the manga.
Koga was originally teamed with Takeda and Ukita as part of the Three Man Army and the only one that did not join Shinpaku. His current whereabouts are unknown.