Yakuza

The Yakuza (ヤクザ) is a recurring antagonistic faction in the Chainsaw Man series. They are a transnational series of organized crime syndicates originating in Japan. A Mafia-like criminal organization, they are known for their strict conduct, organized fiefdom and illegitimate activity. In the context of the story, they employ vulnerable individuals to hunt Devils for them, such as with Denji, as a major business venture.

Past
Denji's father sustained an enormous debt to the Yakuza for unknown reasons, which was passed to his son.

Introduction arc
A sect of the Yakuza made a contract with the Zombie Devil. However, they were all murdered by Denji as revenge for betraying him.

Katana Man arc
Katana Man and Akane Sawatari sought revenge against Denji on behalf of the Yakuza for killing Katana Man's grandfather, who was a Yakuza handler. They waged war on Tokyo Special Division 4, killing many of its members, before Katana Man was defeated and Sawatari was killed.

Trivia

 * Despite being a notorious criminal organization themselves, a Yakuza leader said that the mafia organizations operating in the Soviet Union and China "makes [the Yakuza] look like angels".