Shinobu
Kocho

Shinobu is the Insect Hashira and the only one who cannot behead a demon. She lacks the raw strength, so she rebuilt swordsmanship around what she can do: a thin blade like a stinger, footwork faster than any other Hashira, and wisteria poison mixed to kill demons from the inside. The Daughter spider demon on Mount Natagumo learned in seconds what that combination means.

The permanent smile is the more disturbing weapon. Her older sister Kanae, the former Flower Hashira, was killed by a demon, and Shinobu wears Kanae's gentle manner like a mask over an anger she freely admits to. She teases, she needles, she offers demons friendship in a voice like honey while describing how she will torture them. At the Butterfly Mansion she is a genuinely good doctor and mentor, which makes the rage underneath more unsettling, not less.

By the Hashira Training arc she has stopped waiting. She has identified the demon that killed Kanae and settled on a plan for it, and she has shared that plan with exactly one person: Kanao, the girl she and Kanae rescued and raised.