Denji [Ryan Colt Levy] is a broke, debt-ridden teen in Tokyo who becomes Chainsaw Man after fusing with his devil-dog Pochita, a transformation that grants him the eerie power to spawn chainsaws from his arms and even turn his head into a towering blade. He starts working for the Public Safety Devil Hunters in Division 4, led by Makima [Tomori Kusunoki], a commanding and enigmatic figure who Denji adores and secretly hopes to impress. In this tight-knit unit he shares a cramped life and dangerous duties with fellow Devil Hunters Aki [Shogo Sakata] and Power [Fairouz Ai], a volatile half-Devil who can manipulate blood. After a tense confrontation with Katana Man, Makima calls in reinforcements and brings in three other half-devils to bolster Division 4: Beam [Natsuki Hanae], a brash Shark Fiend who quickly earns Denji’s wary respect, along with Violence Fiend [Yûya Uchida] and Angel Devil [Maaya Uchida], each with their own dark edge and abilities. The film opens with Denji grappling with strange dreams of a mysterious door, trying to explain them to Power, who responds with a brutal, yet comic, punch that underscores their volatile workplace and the risks ahead.
Beam’s arrival shifts the dynamic inside Division 4, as the eager young fighter is ready to follow Denji’s lead and throw himself into every mission. Makima assigns Beam to partner with Denji while Power is temporarily out of commission, and Denji must navigate a growing sense of responsibility as well as the pressure to prove himself worthy of Makima’s confidence. The bond between Denji and Beam forms a tense but functional alliance, with Beam’s zeal sometimes clashing with Denji’s cautious, practical approach. Their days are filled with patrols, close calls, and the ever-present lure of the door DenjiDreams about, a door that seems to promise answers at a price he cannot yet pay.
A turning point comes when Makima arranges a full-day movie date for Denji, a moment that reveals a softer, more human side of the usually stoic hunter and his crush on Makima. The shared tears they shed during the final film become a spark that pushes Denji toward trying to do good in the world—he begins donating to victims of Devil attacks and starts contemplating asking Makima to officially become his girlfriend. Yet the calm is short-lived, because Denji’s next encounter will shake him to his core: Reze [Reina Ueda], a mysterious teenage girl who appears in a quiet moment inside a phone booth and later in a cafe, drawing Denji toward a dangerous path. Reze’s flirtatious, dangerous charm pulls Denji away from the safety of Division 4 and into a complicated attraction that test his loyalties to Makima and his growing sense of self.
On the streets, Aki and Angel patrol as they prepare for another showdown with Gun Devil. The relationship between Aki and Angel is fraught, as Angel, in his half-Devil form, has become numb to human suffering and often refuses to grant mercy to those who plead for death after a Devil attack. This cold detachment forces Aki to confront the harsh realities of their mission, and Makima’s utilitarian view of such sacrifices adds extra pressure to the duo. As tensions rise, Captain Kishibe [Kenjir Tsuda] makes his presence felt, offering blunt counsel and strategic pressure as he pushes Aki to leverage Angel for the team’s broader goals. In the background, an assassin known as Mohawk Man, aligned with the Typhoon Devil, begins moving into the spotlight, cutting a brutal path toward Chainsaw Man and setting the stage for a larger, grimmer confrontation.
Denji’s time with Reze grows more intimate as she invites him to break into a school late at night and later to a nearby cafe where she works. She flirts with him, then proves her danger by revealing a deeper, more ruthless purpose. Reze turns out to be the Bomb Devil, a hybrid whose explosive power is tethered to a living thread that she can pull to unleash devastation. When she lures Denji toward a late-night fireworks plan, he finds himself torn between his lingering feelings for Makima and the dangerous pull of Reze’s world. She presses him to abandon Public Safety and run away with her, and their chemistry turns increasingly volatile as Reze delivers a chilling kiss before biting out Denji’s tongue and threatening his life. The moment is interrupted when Beam, alerted by scent, arrives to pull Denji from harm, revealing the depth of Reze’s deception and her true identity.
From there, a brutal chase bursts into the street and into a Division 2 hideout, where Denji is carried to safety as Reze decimates the other Hunters. A dizzying sequence of explosions, blood, and rapid shifts in momentum follows, pushing Denji to the edge of his limits. Despite the odds, Denji staggers back into battle with the help of Aki, Angel, and Beam, who fight to keep him alive as Typhoon Devil’s power swirls around them. Angel even uses the blood of a dying woman to revive Denji, a grim reminder of the cost of their world, while Aki’s life takes a toll after a dangerous contact with Angel.
Realizing that conventional swordplay won’t stop Reze, Denji improvises with the loose chains on his arms, finding a way to leverage his own chainsaw powers against the Bomb Devil’s explosive form. He charges into the fight on Beam’s Shark Fiend form and drives a brutal, chaotic assault that tears through the street and into the water. Denji wraps Reze in his chains and drags her underwater, suppressing her explosive potential and buying time for a more decisive end. Reze is left weakened but alive on a beach, and Denji’s rescue is bittersweet as she revives—an ominous sign that their bond may have deeper consequences. Reze’s final choice is a paradox of closeness and betrayal; she attempts to return Denji’s affections, then sharply turns, delivering a fatal gesture that leaves him reeling.
In the wake of Reze’s apparent betrayal, Public Safety leadership moves to sever the last tether between Denji and the Bomb Devil. Makima confronts Reze in an alley and detonates a surgically precise intervention, severing Reze’s arm as she attempts to detonate herself. Angel steps in, and with a decisive spear thrust, Reze falls. Yet even in death, Reze’s presence lingers in Denji’s mind as he waits at a cafe, wondering what comes next. Reze’s boss confirms she’s gone for good, and the news lands with a hollow ache. Power bursts back into the scene with a triumphant entrance, a bouquet of flowers in hand that she reads as a gift meant for her, and Denji, distracted by mixed feelings, contemplates how best to respond as a distant clanging from the forbidden door echoes in the background.
And then, after the credits roll, the day remains unfinished. Denji waits at the cafe, still tethered to a world where love and violence blur, while Power’s return and the clanging sound behind the door hint at new mysteries and challenges to come. The film closes on a note that mixes tenderness with danger, leaving him—and the audience—with questions about loyalty, desire, and the price of power in a city where every demon is only a heartbeat away.
