The Hellfire Club is a club of comic book supervillains in the Marvel Comics, and are frequent foes of the X-Men. It was created by Chris Claremont and John Byrne, and first revealed in X-Men #129 (1979). The club is based both on the real 18th century Hellfire Club, and the modern-day version that appeared in The Avengers television series.

The Hellfire Club counts among its members many famous and influential members of society. Membership is passed on to descendants, and can be earned through wealth or influence. The club has branches in New York City and London.

Unbeknownst to most members of the club, the organization is ruled by a Council of the Chosen. This secret group later renamed itself the Inner Circle and assumed the titles of chess pieces. Originally the Inner Circle was composed of normal humans, but was slowly infiltrated and dominated by super-powered mutants that use the organization to further their conspiracies opposed by the X-Men.

The Hellfire Club first came to the attention of the X-Men when agents of the Hellfire Club kidnapped several X-Men and took over the mind of Phoenix. Though the X-Men unravelled the Hellfire Club's scheme, the meddling with Phoenix's mind led her to become Dark Phoenix.

Known members of the Inner Circle

Constant intrigue and politicking has resulted in many changes to the membership of the Inner Circle. The Inner Circle's key positions and the people known to have held those positions at one time or another are listed below.

• Black King: Sebastian Shaw, Shinobi Shaw, Blackheart
• White King: Edward "Ned" Buckman, Donald Pierce, Benedict Kine, Magneto and Storm jointly, Daimon Hellstorm
• Black Queen: Selene, Benazir Kaur, Phoenix
• White Queen: Paris Seville, Emma Frost, Reeva Payge, Courtney Ross
• Black Bishop: Harry Leland
• Black Rook: Friedrich von Roehm, Madelyne Pryor, Sunspot
• White Rook: Emmanuel DaCosta, Trevor Fitzroy

Although the Inner Circle is fairly secretive, there are a number of characters that have access to or are part of the circle despite lacking an official title. Mastermind was a probational member of the club for a long time and often worked closely with the Inner Circle. Tessa, later known as the X-Man Sage, served as an advisor to Shaw and then Sunspot. Angel and Iron Man are hereditary members of the club, although they have rarely visited, and are not aware of the plans of the Inner Circle.

Magneto briefly took the title of Grey King after being voted out of the Inner Circle by Sebastian Shaw, Emma Frost and Selene.