Denji is a teenager who lives his life as a Devil Hunter.

Aiming to pay off the debt he inherited from his father, he starts hunting devils for the yakuza with his buddy Pochita, a "Chainsaw Devil", while living a tragically poor life.

Just when things seem like they couldn't get any worse, Denji gets betrayed and killed by the yakuza. As Denji starts passing out, he hears someone calling from inside his head...

Sawatari sends the "Ghost Devil" after Hayakawa, and he's nearly killed before the "Ghost Devil" stops and hands him a cigarette with a message from Himeno. The words inside give Hayakawa the strength to kill the “Ghost Devil” and capture Sawatari.

Meanwhile, Denji heads into his rematch with Samurai Sword. With a pull of the starter on his chest, he transforms into Chainsaw Man.

And now, the last battle between Chainsaw Man and Samurai Sword has finally begun...