Right on the surface, the Hellfire Club is an international social club that caters to the ultra-elite. Behind the scenes, though, the Club’s Inner Circle is more of a secret society bent on domination. The members dress in 18th century period costumes and take on the names of chess pieces, which makes them sound like bunch of vampires. They’re not, but they are infested with mutants.
References: [wikipedia.org: Hellfire Club (comics)]
[writeups.org: Hellfire Club]
[org]
Metahuman Database 