When his father died, Denji was stuck with a huge debt and there was no way to repay it. Thanks to a demon dog he saved named Pochita, he is able to survive through odd jobs and kill demons for the Yakuza. Pochita's chainsaw powers come in handy against these powerful demons. When the Yakuza betrays him and is killed by the Zombie Devil, Pochita sacrifices himself to save his former master. Denji is reborn as a hybrid known as Chainsaw Man