Chainsaw Man places Denji in a brutal world where devils are hunted by people willing to risk everything for survival and profit. After inheriting his deadbeat father's overwhelming debt, Denji works for the yakuza as a devil hunter with only Pochita, the chainsaw devil, at his side. Together they take on dangerous jobs just to keep enough money flowing, while Denji clings to painfully ordinary dreams: good food, a comfortable life, and a beautiful girlfriend.
When the yakuza betray him, Denji is killed, but an old contract allows Pochita to merge with his body and revive him as a hybrid who can transform parts of himself into chainsaws. His new power makes him a threat and a weapon at the same time, drawing the attention of Makima, the Public Safety Bureau's elite devil hunter. She brings him into her organization and lets him live under her command, and Denji throws himself into the Bureau's violent missions while still chasing the simple happiness he has always wanted, even as every battle pulls him deeper into absurd danger.