Gou Koga is a big, imposing guy with spiky orange hair and a rough, biker-like appearance. He's genuinely strong—even without his doll, he can physically overpower Ichigo in hand-to-hand combat. His doll is Dalk, a shapeshifting metallic being who can manipulate her molecular structure however she wants.
His real name is Claude Gauguin, and he's a European Bount who's been around for over twelve generations. When Kariya started planning to destroy Soul Society, Koga thought it was insane and tried to stop him himself. That didn't go well. He ended up fighting Tōshirō Hitsugaya instead and got completely shut down—both he and Dalk couldn't handle Hitsugaya's overwhelming cold and ranged attacks.
He survived the fight, though. Yoruichi secretly brought him to Rantao's place to recover, and that's where things changed for him. Learning that he was literally the last Bount alive, Koga came to terms with what his race had done, especially Kariya's violence. He's last seen living peacefully with Rantao.
What happened to Dalk is never directly addressed. Given that Bounts are supposed to die when their dolls do, she either still exists somehow or Koga's just an exception to the rule—similar to how Yoshino worked.
Content compiled by AnimeList.moe from publicly available sources.
