Jubei moves through this world like death itself, and every frame exists to prove it. The plot is just scaffolding for sequences that make you forget to breathe, demons with bodies that break physics, fights that escalate past human scale into pure spectacle, all rendered in hand-drawn animation that makes modern CGI look timid. This is what anime action looked like when it had nothing to prove except that it could out-brutal live-action cinema.

Jubei Kibagami is a wandering swordsman for hire in feudal Japan, left without a master by an old betrayal and tired of political scheming. He is pulled back in when he rescues Kagero, a female ninja and the last survivor of her clan, from a man whose body can turn as hard as stone. Kagero is still carrying out her team's final mission, looking into a strange plague that wiped out a whole village. Jubei wants no part of it, but the Devils of Kimon, a band of ninja with supernatural powers, make staying out difficult. Then a government spy poisons him and promises the cure only if he uncovers what the Devils are really after and how they tie into the plague. The search points toward hidden leaders, a scheme to topple the government, and a man from Jubei's past he never expected to meet again. The atmosphere is relentlessly bleak, painted in blood and shadow as the pair encounter increasingly grotesque horrors that sit somewhere between nightmare and reality.