Taichi Koga/History

== Plot==
Koga is first shown when Takeda shows his desire to fight Kenichi. When Kenichi and Miu were walking home from shopping, Koga and his gang ran into them and prepared to fight them. He showed an interest in Miu, but once she beat all of his men and kicked him, he grew to develop a grudge against him. Kenichi would fight him and Kenichi would deliver a shallow punch on his chin and cause him to lose his balance and Kenichi defeated him. He later appeared to give Takeda his farewell beating for leaving Ragnarok and was shocked that Ukita betrayed them and sided with Takeda by throwing Koga in the trash. When Ukita was caught, he planned to jump up and break his arm despite the others' protests but was thwarted by Kenichi's punch in the back. The next day, he laughed at Kisara's loss against Miu. He traveled with Kisara to ruin Miu's play, but when Kenichi showed up and stopped them, Koga was again defeated by Kenichi. When Kisara's gang was joining Shinpaku, Koga was forced to get along with the other members of the alliance. However, he was a double agent for Loki. When he tried to give Niijima some soda with laxatives, Niijima saw through this and forced Koga to drink it and ran away needing a bathroom. His current whereabouts are unknown, but with Ragnarok disbanded, it's likely he is still a thug or forced to go back to school.