Chainsaw Man is the result of a young man who is broke and a chainsaw dog monster.

Denji was an amateur devil hunter attempting to make it in a hostile environment. He was slain while doing a job, but his pet devil Pochita brought him back to life so that he might become Chainsaw Man, a new and terrible creature.

The mysterious Santa Claus enters the fray as Quanxi and the Special Division members compete for control of Denji. The darkness and sorrow that are about to be unleashed, however, will catch everyone off guard because things are not as they seem.