After years of theories and anticipation, Ironheart finally debuted Mephisto, Marvel Comics’ stand-in for the Devil, in the MCU. And he’s played with evil glee by none other than Sacha Baron ...

"The influence of Mephisto knows no bounds." Here's everything Marvel and 'WandaVision' fans need to know about Mephisto, from his comic book past to his possible role in Phase 4 of the MCU.

Wherever Mephisto pops up next in the MCU, there needs to be some kind of scene or moment of dialogue where he addresses the Snap, the Blip, and all those souls being snatched and then in an instant.