Sentarō Kotsubaki

Sentaro keeps a short goatee below a head of dark hair. Rather than the plain shihakusho, he wears a personalized take on it, adding a slim white band across his forehead and pale straps looped over his shoulders that meet in a knotted circle behind his back.

Devotion to his captain drives almost everything Sentaro does, and he will seize any chance to look good in Ukitake's eyes. That drive puts him in constant friction with Kiyone Kotetsu, the two bickering and scuffling over who admires their captain more. The rivalry is not genuine spite, though, since he moved to save her once she was hurt. He also tends to bellow, delivering even routine reports at a shout.

A native of Rukongai, Sentaro rose to co third seat of the division alongside Kiyone in the wake of Miyako Shiba's death. During the Soul Society arc Ukitake orders him to carry the unconscious Rukia back into her cell, a task he performs while quietly apologizing to her, and he is later knocked aside by Sui Feng before Unohana ferries the wounded away inside Minazuki. He and Kiyone go on to help destroy the Sokyoku.

Across the Thousand Year Blood War he alerts Ukitake to the Wandenreich pillars, follows the captain through the invasion, and reaches Wahrwelt with the surviving Shinigami, where Lille Barro shoots him down. Later, gathered with the other lieutenants in the Human World for the Echoing Jaws of Hell, he rushes to Kiyone's side when she is impaled. By then he holds the rank of lieutenant under Rukia. In combat he carries the high spiritual power expected of his office and enough Shunpo to appear the instant he is summoned, while his Shikai has never been shown.