Mephisto officially debuts in Ironheart finale as Sacha Baron Cohen surprises cast and fans

Marvel’s “Ironheart” has finally introduced one of its most speculated villains: Mephisto. After years of fan theories and speculation, the demonic character made his on-screen debut in the series finale on Disney+, confirming long-standing rumors about actor Sacha Baron Cohen’s role.

Speaking to TheWrap, series lead Dominique Thorne revealed that even the cast had been kept in the dark. “The name in the script kept changing,” she said. “It wasn’t until we shot that final scene, I’m sitting face to face with Sacha Baron Cohen, where I’m like, ‘Oh, he said it. It’s Mephisto.’”

While fans initially believed Parker Robbins’ mystical powers came from Dormammu — a powerful entity introduced in Doctor Strange — the finale overturned that theory, revealing Mephisto as the true force behind the magic. Thorne noted that the creative team was mindful of fan anticipation surrounding the character and aimed to deliver a memorable and impactful reveal.

In the final moments of the episode, Riri Williams (Thorne) appears to make a deal with Mephisto to bring back her best friend, Natalie — a decision driven by deep personal loss. As the scene closes, Riri bears ominous magical markings on her body, mirroring those seen on Robbins, suggesting major consequences ahead.

When asked whether this marks a turn to the dark side, Thorne responded cautiously: “We might need to keep an eye on her.” She acknowledged the emotional complexity of her character’s choice, especially for a young adult dealing with unresolved grief.

While Thorne expressed interest in exploring a darker character arc, she also emphasized Ironheart’s significance as a symbol of hope for young viewers. As fans speculate on where Riri’s journey will go next, one thing is certain — the MCU just got a lot darker.

“Ironheart” is now streaming exclusively on Disney+.