Aida

Aida wears his brown hair slicked and parted to the right, and a long nose sits squarely at the center of his face above a pair of dark eyes.

At the outset Aida is moody and withdrawn, keeping his misgivings about the newly appointed Shūsuke Amagai quieter than his blunt comrade Inose. As the division's teamwork improves under the new officers, he grows bolder and more candid, freely offering criticism even to his lieutenant while taking a brighter view of the squad's prospects. His hunger to prove himself can override his judgment, though, and he willingly defies a superior's orders to charge into battle, worn down by the low regard in which his division is held.

Word that the Third Division will receive a captain none of them have met throws the barracks into a stir, and Aida shares Inose's skepticism even as their lieutenant Izuru Kira welcomes the change. Amagai earns some goodwill by sympathizing with their unease, though a welcome party ends with the new captain fainting after a single drink. When roughly thirty Menos surge into the Dangai, the division is sent in, and a still tipsy Amagai stuns everyone by destroying a Kōtotsu to shield them.

Over the following days Aida warms to Amagai's third seat, Makoto Kibune, bonding over drinks and thriving under fresh group drills that sharpen the squad's coordination. Mounting oddities around Kibune, an execution pit rigged to give way and a gravely injured recruit, stir suspicion, yet Aida's eagerness pushes him to follow Kibune and disobey Izuru during what turns out to be a staged test of Amagai's command. The truth finally surfaces when Kibune is unmasked as a traitor and turns his Zanpakutō Reppū on the squad; Aida is flung across the arena but survives, watching Izuru at last bring the traitor down. Academy trained and steady with a blade, he handles coordinated footwork under a superior's guidance, though his own Zanpakutō and its release have never been shown.