Mephisto has officially made his MCU debut in the final episode of Ironheart. The long-speculated demonic villain is finally here, and he’s brought with him a chilling blend of charisma, chaos, and godlike power.

For the past four ears, we've had many wild theories as to when and where we'd see the demon lord Mephisto in the MCU.

The Ironheart finale really showed that the devil was truly in the details.