Gō Koga

Koga cuts an imposing figure, broad and heavily built with orange-brown skin, pale green eyes under thin brows, and a large nose. His short dark red hair wraps his head into sideburns, a beard, and a split, spike-shaped mustache, while the crown of it is instead orange, longer, and jagged. He tends to wear a wireless pair of bulky black headphones slung round his neck, a dark green tank top, blue jeans on a plain-buckled belt, a pouch strapped diagonally across one thigh, and simple black shoes. Centuries earlier, during his time raising Cain, his hair was fully red and worn long at the back, and he dressed in a tan vest over a green-collared shirt cinched by five stacked belts, with boots laced up over his shins.

Terse, serious, and coldly efficient, Koga carries the pride of his race, viewing his Bount nature as proof of a chosen humanity and his centuries of self-discipline as the summit of human strength. He shares the slight cruelty common to his kind, untroubled by feeding humans to the Bitto or hearing of Hō and Ban's deaths, yet that hard shell hides a cynic who thinks it folly to believe anyone can be saved and who candidly weighs the limits of his own power. He is deeply philosophical about the sorrow of an existence that outlasts everyone around it, watching the young age and die while he endures. Much of that grief traces to Cain, a young Bount he was asked to train as a favor to Kariya and came to love like a son; when Cain died summoning a Doll against his guidance, Koga blamed himself and swore off seriously harming young people who still had lives ahead of them.

Beneath his gruff surface he is far from unkind, warning bystanders of the danger Kariya poses, sparing Soul Reapers who merely protect souls, and longing above all for peace between his people and Soul Society. His sharp, analytical mind lets him read an opponent's powers and strategy, and it earned him a teacher's role among the Bount as well as standing as one of only two able to work their tribe's complex spells. His closest bonds are with Maki Ichinose, the one person he relaxes around, and with his Doll Dalk, whom he treats as an equal rather than a servant and comforts gently even as she is destroyed. His loyalty to Kariya, however, has always been wary; convinced from the start that the man was an uncontrollable blade, he finally turns on him upon learning Kariya would let the Bount die out and squander the power of the Jōkaishō on mere annihilation.

Long ago Koga lived alone on a small European farm, where Kariya brought him the unruly young Bount Cain to raise. The two bonded over farm labor, and after Cain witnessed Koga summon Dalk to drive off a murderous mob, he grew determined to earn a Doll of his own. Koga eventually judged him ready but insisted on overseeing the ritual; the impatient Cain performed it alone in the night, and his newborn Doll turned on him and killed him. Devastated, Koga and Kariya raised a monument to the boy and chose to live together against the loneliness of their kind, later saving Maki Ichinose from a Hollow and taking him in.

When Kariya sets his plan to wipe out the Seireitei in motion, Koga answers the summons and helps capture Uryū Ishida and Yoshino Sōma. After drinking the Bitto serum that multiplies his strength many times over, he confronts Ichigo, only for Ichigo's inner Hollow to cut Dalk down before Izuru Kira intervenes and Koga chooses to spare his opponent. He helps forge the Senkaimon into Soul Society, routs the divisions sent against him, wins over the people of Kusajishi, and clears the White Road Gate by defeating Jidanbō Ikkanzaka. His path breaks with Kariya's once he learns the true, genocidal purpose of the Jōkaishō; for refusing to go along, Kariya thrusts a hand through his gut and abandons him. Koga heals himself with reishi and hunts Kariya down, but crosses Captain Tōshirō Hitsugaya instead, whose ice shatters Dalk and buries him. Yoruichi Shihōin rescues him and carries him to Ran'Tao, and once Kariya is dead Koga, now the last living Bount, quietly accepts his race's fate and asks that Ichigo be thanked for ending Kariya.