Suì-Fēng

Suì-Fēng is the captain of the 2nd Division and Commander-in-Chief of the Onmitsukido, which makes her responsible for both the Gotei 13's assassinations and its internal security. She earned the position by being better at the work than anyone available, and she has never once been comfortable in it.

Yoruichi Shihōin is the reason. Suì-Fēng served as her bodyguard, worshipped her completely, and was left behind without explanation when Yoruichi fled Soul Society with Kisuke Urahara. A hundred years of that produced a captain who trusts nobody and takes any hint of insubordination personally, and her first act on seeing Yoruichi again is to attack her.

Suzumebachi is the smallest Zanpakutō in the series and the most direct: a stinger on one finger that marks a target, and a second strike on the same mark kills them outright, regardless of what they are. Her Bankai is the opposite of that in every respect, a shoulder-mounted missile she considers vulgar precisely because assassination should not be loud. She spends the Wandenreich war having that Bankai stolen and then given back, and Marechiyo Ōmaeda, who she has insulted for years, is the one who carries her out.