Dormammu is a fictional character in the Marvel Comics universe. He is a demon and a powerful sorcerer from the "Dark Dimension". He frequently battles Doctor Strange.

Dormammu resembles a massive humanoid with a flame-cloaked head. His sister, Umar, is more human in appearance, though her head also bears a mantle of flames. The siblings were once two of the Faltine, a race of extra-dimensional energy-based beings. However, they became greedy, bonding matter to themselves to accumulate power. The other Faltine exiled the siblings to the Dark Dimension, where they accumulated power and eventually came to rule. Doctor Strange and his lover and partner, Umar's daughter Clea, have fought both of the Faltinians numerous times, deposing them on several occasions. However, Dormammu and Umar continue to further their arcane schemes and menace both the Dark Dimension and the Earth.