Power

Loud, filthy, and utterly without shame, Power crashes into Chainsaw Man as the series' chaos agent — a fiend wearing a human corpse who would rather brag about her superiority than lift a finger to help anyone. She belongs to Tokyo Special Division 4, the ragtag experimental unit assembled by Makima, and nominally serves as a Public Safety Devil Hunter alongside Denji and under the watch of Aki Hayakawa. In practice she treats the job as an inconvenience, fighting only when there's something in it for her and vanishing the moment a battle turns against her. As the physical host of the Blood Devil, she commands blood itself — hers and, eventually, anyone else's — turning it into blades, shields, and grotesque tools of war. Beneath the cat obsession, terrible hygiene, and constant scheming, though, she becomes one of the emotional cores of the story's first arc, and her bond with Denji reshapes both of them by the time her arc reaches its devastating conclusion.

Power is not a human being who became a devil's host by accident — she is a fiend, meaning the Blood Devil took over a corpse and reanimated it as its own vessel. This distinction matters enormously in the world of Chainsaw Man: fiends are devils wearing dead human bodies, and most Devil Hunters regard them as monsters to be exterminated on sight rather than colleagues to be trusted. Power's recruitment into Tokyo Special Division 4 is itself an experiment by Makima, who gathers fiends and hybrids specifically because their inhuman power makes them useful weapons against other devils, even as their loyalty remains suspect.

Little is revealed early on about what Power's human host was like in life, and Power herself shows no interest in that history — she identifies completely as the Blood Fiend, not as whoever the body once belonged to. She was already operating as a Devil Hunter of sorts before Denji's arrival, undisciplined and largely unsupervised, which explains why her habits are so feral: she is essentially a devil playing at being a person, with none of the socialization that would normally smooth out those rough edges.

Power is childish, greedy, and almost pathologically self-interested. She picks fights when she's confident of winning and something worthwhile is on the table, and she flees without a shred of embarrassment the instant the odds turn against her. Her sense of self-worth is bound up in her identity as a fiend — she frequently and loudly insists she is superior to the merely-human Devil Hunters around her, using that claimed superiority as both a boast and a shield against ever admitting fault.

She has no innate loyalty to humanity and says so openly, stating she'd throw in with whichever side looks likely to win a given conflict. This isn't villainy so much as amorality: right and wrong barely register with her compared to what benefits Power in the moment. She is rude by default and treats basic courtesy as something other people should extend to her rather than something she owes back.

Her domestic habits are a running gag and a genuine character trait — she admits to rarely bathing and rarely flushing the toilet, and she considers humans oddly precious for caring so much about hygiene in the first place. Yet for all this self-centered abrasiveness, Power is not incapable of attachment. Her love for her pet cat Meowy and the grudging, chaotic partnership she forms with Denji reveal a capacity for genuine feeling that she'd never admit to outright, and which slowly complicates her claims of total selfishness as the story progresses.

Power stands 170cm tall, with a striking devil-marked appearance that sets her apart at a glance from ordinary humans: sharp yellow eyes with slit pupils, small horns, and long blonde hair that frames an expression usually somewhere between smug and delighted. Her design leans into the feline and predatory, fitting for a character who fixates on cats and who moves through most scenes like she owns them.

Her general presentation is deliberately unkempt, in keeping with her self-described disinterest in hygiene — she's a character whose grubbiness is played for both comedy and a subtle reminder that she isn't really operating by human standards of self-care to begin with.

Power is the host of the Blood Devil, and her core ability is total control over blood — beginning with the blood inside her own body, which she can reshape, harden, and weaponize at will. She forms blades, spears, and barriers out of her own blood on demand, giving her a versatile offensive and defensive toolkit that requires no external weapon. Because the blood is drawn from herself, sustained or excessive use comes at a real physical cost, though as a fiend she recovers from injuries far more readily than a human would.

As a devil-turned-fiend, she possesses superhuman strength, durability, and resilience well beyond ordinary human limits, letting her trade blows with other devils and fiends in ways no unaugmented Devil Hunter could manage. Her fighting style is aggressive and improvisational rather than disciplined, matching her personality — she favors overwhelming, showy displays of force when she's sure of victory, and disengages entirely rather than grinding through a fight she might lose. Later in the story her control over blood expands into more dangerous territory, allowing her to manipulate blood beyond her own body, which raises the stakes of her power considerably.

Denji is Power's assigned partner in Special Division 4, and their relationship starts as pure antagonism — two selfish, undisciplined forces of nature who can barely stand each other, prone to petty theft, bickering, and outright violence between themselves. Over time this friction curdles into something closer to genuine, if constantly denied, camaraderie; Power comes to treat Denji as hers to torment and protect in equal measure, and he becomes one of the only people she seems to actually care about beyond her own immediate wants.

Aki Hayakawa nominally supervises both Power and Denji, and functions as the long-suffering adult in the room forced to manage two subordinates who barely respect the concept of rules. Power delights in provoking him and treats his exasperation as entertainment, though a begrudging respect exists underneath the antagonism.

Makima sits above all of them as the architect of Special Division 4, and Power's relationship to her is coloured by the same self-preservation that defines most of her choices — she serves under Makima not out of loyalty but because it's currently the safer option, consistent with her stated willingness to back whichever side is winning. Her cat, Meowy, is the one unambiguous soft spot in her personality, a source of affection she doesn't bother rationalizing away the way she does everything else.

Power enters the story as comic relief and a wildcard fighter, her chaotic unreliability providing both laughs and genuine tension since no one, including her own teammates, can be sure whether she'll show up for a fight or bolt at the first sign of danger. As Special Division 4's missions escalate, she's repeatedly thrown into combat against devils and rival fiends where her blood-manipulation powers make her a serious asset despite her attitude.

Her dynamic with Denji forms one of the emotional throughlines of the arc, and their gradually deepening bond — forged through shared recklessness and dysfunction rather than anything resembling sentimentality — becomes central to how both characters are pushed to their limits. As the first arc builds toward its climax, Power is placed in increasingly dangerous circumstances that test whether her professed selfishness can hold up against loyalty to the people she's grown attached to, culminating in one of the story's most pivotal and emotionally consequential turns.