- Joyce Byers - Winona Ryder
- Mike Wheeler - Finn Wolfhard
- Eleven - Millie Bobby Brown
- Dustin Henderson - Gaten Matarazzo
- Lucas Sinclair - Caleb McLaughlin
- Will Byers - Noah Schnapp
- Max Mayfield - Sadie Sink
- Nancy Wheeler - Natalia Dyer
- Jonathan Byers - Charlie Heaton
- Steve Harrington - Joe Keery
- Robin Buckley - Maya Hawke
- Erica Sinclair - Priah Ferguson
- Karen Wheeler - Cara Buono
- The title of the episode was revealed on November 6, 2019, on the occasion of Stranger Things Day.
- The episode title is a reference to the organization The Hellfire Club from Marvel's X-Men comics.
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