Chainsaw Man, Vol. 1: Dog And Chainsaw by Tatsuki Fujimoto

Broke young man + chainsaw demon = Chainsaw Man! Denji was a small-time devil hunter just trying to survive in a harsh world. After being killed on a job, he is revived by his pet devil Pochita and becomes something new and dangerous—Chainsaw Man! Denji’s a poor young man who’ll do anything for money, even hunting down devils with his pet devil Pochita. He’s a simple man with simple dreams, drowning under a mountain of debt. But his sad life gets turned upside down one day when he’s betrayed by someone he trusts. Now with the power of a devil inside him, Denji’s become a whole new man—Chainsaw Man!