Gō Koga

is a Bount, and the one closest to Jin Kariya.

Appearance
Koga has red hair cut short, with a spiky orange center. He is a very large and muscular man, usually wearing a sleveless shirt and large headphones around his neck.

Personality
Despite his size, this man is kind. When he took Cain in, he tried to protect the young man from his doll, but failed. Ever since, he refuses to hurt children, which is why he turned against Kariya. After realizing he was the only Bount left, he apologized for their harsh actions.

Synopsis
Koga was first seen trying to take Yoshino Sōma and Uryu Ishida back to Kariya's mansion. He breifly fought Yoshino's doll, Goethe, but used Dalk to overpower her. After her soul was used to create the bitto, he faught Ichigo, because the latter was trying to protect his friend. Koga would have won, but Izuru Kira used his zanpakuto's ability to bring Dalk to her knees. He is then forced to retreat.

After breaking through to the Soul Society, he helps Kariya and Maki Ichinose rally forces from the 79th District of Rukon. When Kariya adsorbs the Jōkaishō, he begins to wonder about his true motives. He then slams Kariya into a wall, and it stabbed through the stomach as punishment.

Going after Kariya, he is sopped by Toshiro Hitsugaya. The two battle, and Hitsugaya appears to have the upper hand, being that metal is vulnerable to ice. However, after Dalk falls, Koga reveals her core is actually a large battle axe. The two continue, but he still fails to beat the captain and loses at his hand.

Ran'Tao finds and saves him, healing his wounds. Realizing he is the last of his kind, he apologizes for their actions and is free to go.

Doll
is Koga's doll. She takes the form of a metal sphere with the Bount seal upon it when sealed. When released, she forms into a rather flirtatious, semi-humanoid/spider-like shape and can control the metal that makes up her body, reforming it into any shape she wishes. She is able to split herself into tiny spheres no bigger than a ball bearing, making it very difficult to destroy her. She uses a variety of attacks in combat, such as creating metallic webs to entrap her opponent, firing pieces of her body as projectiles, and even turning her arms into machine guns to fire makeshift bullets through. After Koga drank the bitto's soul elixir, Dalk became even more spider-like, retaining only her humanoid torso. She also gained much more metal to work with. Dalk has trouble with cold-based attacks, which make it difficult for her to split her body apart. As a heavy, metal-based creature, she is also vulnerable to Izuru Kira's Zanpakutō, Wabisuke, which doubles the weight of anything it cuts. In contrast, Dalk seems to be nearly invulnerable to heat. It is revealed in episode 104 that Dalk's core form is a large battle axe that Koga wields. 

Trivia

 * He is the last surviving Bount in the series.
 * When he asks Yoruichi to tell Ichigo thank you, she completely forgets about it, due to the upcoming battle against the arrancar.