Shinji
Hirako

Shinji Hirako transfers into Ichigo's class with a backwards grin, an antique haircut, and an offer: join the Visored, the exiles who learned to wear their Hollows instead of being eaten by them. He spends his introduction acting like a pest, and then the show reveals what he actually is, the former captain of the 5th Division, and what happened to him, which is the series' oldest crime.

A hundred years earlier, Shinji chose Sousuke Aizen as his lieutenant specifically to keep an enemy where he could see him, and watched him anyway as Aizen Hollowfied eight captains and lieutenants, including Shinji, and let Urahara take the blame. The Turn Back the Pendulum flashback is his arc's spine: a century in exile in the Human World, training in a warehouse, hating a man the rest of the world thought was a saint.

His Zanpakuto fits a man nobody takes at face value. Sakanade's inverted world reverses his opponent's senses: left is right, forward is back, and watching Aizen's forces fumble through it in the fake Karakura Town is his revenge in miniature. After the war the Gotei 13 gives him his captaincy back. In the Blood War he leads from the front, saving Momo Hinamori from Gerard Valkyrie in Wahrwelt and donning the Hollow mask beside Rose and Love to show the Quincy giant what the Visored call a miracle.