The Dungeons & Dragons club at Hawkins High School in season 4 of "Stranger Things" is the Hellfire Club.
The club is led by Eddie Munson, an eccentric senior who organizes elaborate D&D campaigns for fellow students including Mike Wheeler, Dustin Henderson, and Lucas Sinclair. Its name reflects the fantasy game’s demon-filled imagery and the club’s outsider reputation at school.
The Hellfire Club becomes central to season 4 when its final campaign occurs on the same night as Hawkins High’s basketball championship. Lucas chooses the game, while Mike and Dustin recruit Erica Sinclair to play in his place. The two events are shown in parallel, linking the club’s fictional battle against Vecna to Lucas’s real-world struggle.
After Chrissy Cunningham is murdered in Eddie’s trailer, frightened townspeople and Jason Carver’s basketball teammates wrongly portray the Hellfire Club as a satanic cult. The club is actually an ordinary student gaming group. The name is also a common mix-up with the Avengers’ Hellfire Club, a separate fictional organization from Marvel Comics.