The Chainsaw Man manga series features an extensive cast of characters created by Tatsuki Fujimoto.
A group of powerful devils based on the Four Horsemen of the Apocalypse who can remember the existence of devils eaten by the Chainsaw Devil, who they battled long ago. They seek to kill or use the Chainsaw Man to fulfill their goals. According to Fami, the horsemen may be related to each other, as she treats Yoru like a younger sibling.
The Public Safety Devil Hunters are an organization of government-sanctioned Devil Hunters in Japan who are sent to dispatch Devils and tasked with resolving devil-related incidents on a smaller scale. They are divided into different "special divisions", including in Tokyo and Kyoto, with Tokyo Special Division 4 being an experimental division.
Individuals who work solo or in groups with private devil hunters. They are similar to bounty hunters and freelancers, meaning that they are not loyal nor officially employed by any government.
The biggest school in Tokyo, which Denji and Asa attend.