Asa Mitaka

Asa wears her black hair, sometimes tinted brown, in two low twin tails that fall to the middle of her back yet read as shorter than they are; in earlier days she kept it at shoulder length. Her dark blue eyes usually sit nearly black, brightening at the irises in certain moments. A high schooler of ordinary height, she starts out lean and fills into a more womanly frame as hunting work makes her stronger. Her school outfit layers a button-up shirt under a pleated pinafore dress with a collar bow, a wide belt, knee-high black socks, and sneakers. Over the course of the story she loses her right arm to Yoshida and then her remaining arm against Pochita, after which Yoru gives up the Tank and Gun Devils, reshaping the pair into weaponized gauntlets in place of the lost limbs. Her later wardrobe shifts to looser tops and dark pants with her hair worn down.

Reserved and prickly, Asa keeps her classmates at a distance and holds a bleak view of people and devils alike, routinely assuming the worst of everyone. She adores cats, valuing them above human lives, and later admits her hostility sprang from envy and a sense of not belonging. Low self-worth sits oddly beside bouts of misplaced confidence, such as her certainty that she could seduce Denji, and her social clumsiness runs so deep that even Yoru reads situations better than she does. Her morality feels manufactured, since she frets over the fallout of her actions far more than their rightness, fearing mistakes above all. When she does slip, she lashes out at those around her before crumbling into self-loathing. She craves recognition yet distrusts closeness, caught in what she calls a cognitive dissonance between dreading solitude and dreading company. Though timid at first, her wish to save Chainsaw Man hardens her into a capable, braver hunter. Once Pochita erases himself and a new timeline forms, she sheds her gloom entirely and lives as a cheerful, well-adjusted teenager.

Yoru revives Asa after her death and seizes her body, leaving half her brain intact because the devil needs a human guide to navigate the world and hunt Chainsaw Man; the two share control, with Asa promised her body back once the mission ends. As the War Fiend's host, she can turn anything she owns, objects or living beings, into a weapon by naming it, with each weapon's strength scaling to the guilt she feels in making it; the gift yields blades from her uniform, a spear from an entire aquarium she buys, and a chainsaw-laden motorcycle. At Fourth East High School she befriends Yuko and crosses paths with Denji, attempting a clumsy romance that collapses before she falls instead for his Chainsaw Man persona after he rescues her from the Falling Devil. An encounter with the Death Devil vaults her into fame as a hunter inside the Chainsaw Man Church. When the Church falls, she turns fugitive and then terrorist, breaking into a Public Safety detention center to free the captive Chainsaw Man. Her bond with Yoru frays as the devil's cruelty and the mounting death toll wear on her, until she resolves to die alongside Yoru to erase war, only for Denji to talk her into trusting that he can save them both. Through the Aging Devil arc she forms a pact with that very devil in exchange for escape and lasting peace, and afterward she stays on the run beside Denji.