Dormammu, also known as the Dread Dormammu, is an evil extra-dimensional being. Dormammu is able to travel from dimension to dimension and drain the life energy out of entire galaxies. He, along with his servant Baron Mordo, are Doctor Strange's archenemies.
Dormammu is believed to be thousands, possibly millions or even billions of years old. Dormammu survives by consuming the souls of living beings in various dimensions. However, at some point Dormammu was trapped within his home dimension which is called the Dark Dimension.
Sometime later Dormammu met a sorcerer named Baron Mordo who became his servant. Mordo's mission was to find a way to release Dormammu from the Dark Dimension and bring him to Earth so that he could consume all life in the universe. However, when Doctor Strange became a sorcerer he made it his mission to stop Mordo from releasing Dormammu.
Wand of Watoomb
Dormammu later learned that Doctor Strange had possession of the Wand of Watoomb which was a magical object that could open a portal and bring Dormammu to Earth. Dormammu then had Baron Mordo send his cultists to the Sanctum Sanctorum to steal the Wand of Watoomb. However, Doctor Strange and Spider-Man were able to stop them.
When Dormammu learned that Baron Mordo had failed to obtain the Wand of Watoomb, Dormammu scolded him for his failure and ordered him to try and steal it again. Mordo later captured Spider-Man and brainwashed him into attacking the Sanctum Sanctorum. During this assault the cultists managed to get the Wand of Watoomb and Doctor Strange was able to free Spider-Man from Mordo's control. Doctor Strange then revealed to Spider-Man who Dormammu was and told him that if they did not stop him it would be the end of the world.
When Spider-Man and Doctor Strange arrived at the Center for Reunification they discovered that Baron Mordo had already used the Wand of Watoomb to open a portal to the Dark Dimension. When Doctor Strange and Mordo began to fight each other Wong warned Spider-Man not to interfere because they were in a mystical battle. However, Spider-Man got tired of sitting on the sideline and jumped through the portal into the Dark Dimension to fight Dormammu. However, when Spider-Man came face to face with Dormammu he realized that he could not defeat him. However, Doctor Strange came through the portal and was able to save Spider-Man and they returned to Earth.
However, as Spider-Man and Doctor Strange got back to Earth, Dormammu reached through the portal, grabbed Mary Jane (who was one of the brainwashed cultists) and puled her into the Dark Dimension. As Spider-Man was about to jump through the portal Doctor Strange stopped him and he told Spider-Man that to come to Earth Dormammu must be invited by one of his followers and that Dormammu would try to trick Mary Jane into inviting him. Doctor Strange then told Spider-Man that Mary Jane must find a way to see through Dormammu's tricks by herself. Inside the Dark Dimension, Dormammu took the appearance of Mary Jane's father, Philip Watson. While in the guise of Philip Watson, Dormammu tried to convince Mary Jane to invite him to Earth. However, Mary Jane was able to see through Dormammu's tricks and refused to invite him to Earth. Mary Jane was then transported back to Earth and Doctor Strange used the Wand of Watoomb to close the portal to the Dark Dimension.
Venom & Carnage
Sometime later Dormammu came up with another plan to get free from the Dark Dimension. Dormammu learned that Stark Enterprises was ding research into inter-dimensional travel. Because of this Dormammu had Baron Mordo set up a technology company using the alias Ardon Broom. Mordo then sold to Stark Enterprises the technology they needed to build a device capable of creating a portal between Earth and the Dark Dimension called the Inter-Dimensional Probe.
Dormammu also had Baron Mordo break into Stark Enterprises and secretly use their computers to bring the John Jameson Probe back to Earth. Dormammu had Mordo do this because he wanted the symbiote which was attached to the probe. The symbiote eventually made it's way back to Earth and bonded to Eddie Brock once again turning him into Venom.
Venom then went to Mordo's lair and talked to Dormammu. Dormammu told Venom of how he was able to bring the symbiote back to Earth. Dormammu then commanded Venom to steal the Inter-Dimensional Probe from Stark Enterprises.
As Venom arrived at Stark Enterprises he was challenged by Spider-Man and War Machine who were trying to stop him. Baron Mordo secretly watched their fight. Dormammu's astral form then appeared to Mordo and Mordo told Dormammu that because of Spider-Man and War Machine they might not get the Inter-Dimensional Probe. However, Dormammu told Mordo that he had a backup plan. Dormammu revealed to Mordo that he had him bring the symbiote back to Earth not only for it's great strength but because it was about to reproduce.
A short while later Mordo was able to find the new new symbiote and gave it to Cletus Kasady who was being held at the Ravencroft Institute for the Criminally Insane. Kasady then took the name Carnage and he went to Stark Enterprises to help Venom. With Carnage's help he and Venom were able to steal the probe and give it to Baron Mordo. Venom told Mordo that he fulfilled his part of their bargain and left. Mordo told Carnage that even with the Inter-Dimensional Probe they needed an equal amount of life force to be sent into the Dark Dimension to replace Dormammu before he could come to Earth. Carnage then attacked random people in New York City stealing their life forces. Spider-Man tried to stop Carnage but failed.
Around this time Iron Man had come to New York City to get back the Inter-Dimensional Probe and ended up joining forces with Spider-Man. However, Spider-Man knew the only way to find Carnage was to ask Eddie Brock (who at this point had been separated from the symbiote). Spider-Man asked Brock where they could find Carnage. However, Brock knew that Spider-Man and Iron Man wouldn't stand a chance against Dormammu. Because of this Brock re-bonded with the symbiote and led them to Mordo's lair.
As Spider-Man, Venom, and Iron Man arrived at Mordo's lair they attempted to stop Carnage and Mordo from freeing Dormammu but failed. Mordo used the Inter-Dimensional Probe to open a portal to the Dark Dimension and Carnage threw a urn containing all the life forces he stole into the portal. The life forces took Dormammu's place in the Dark Dimension which allowed Dormammu to come to Earth.
While Iron Man and Venom fought Dormammu, Spider-Man adjusted some controls on the Inter-Dimensional Probe. By doing that Spider-Man was able to reverse the polarity of the portal and Dormammu and Carnage were sucked into the Dark Dimension. Spider-Man then closed the portal and Iron Man destroyed the probe.
The true extant of Dormammu's magic is unknown. According to Doctor Strange, Dormammu has ultimate power.
It is known that he can absorb the life energy out of whole universes.
Within his own dimension Dormammu was able to increase his size and become a giant.
Dormammu is also able to shapeshift. Dormammu was once able to shapeshift into Philip Watson, Mary Jane's father, and a dragon.
Dormammu can fire beams of magic energy from his eyes.
Dormammu could also use his powers on Earth even though he was trapped in the Dark Dimension. However, this power was limited. Dormammu once took possession of Baron Mordo's body to fight Doctor Strange and was able to fire a magic bolt at his enemies.
In the comics
Dormammu, along with his sister Umar, are members of an extra-dimensional society of energy beings called the Faltine. Unlike other Faltinians they were not perfect copies of their progenitor Sinifer given some unknown mutation and they hungered for matter instead of energy. They were banished from their home dimension for turning Sinifer into matter, which was considered the equivalent of murder.
Dormammu and Umar eventually discovered the Dark Dimension and insinuated themselves into the role of adviser to King Olnar. In exchange for power and protection, Dormammu and Umar taught Olnar how to exploit the natural pocket warps of the Dark Dimension and absorb other dimensions into it.
When Olnar died in an attempt to conquer the realm of the Mindless Ones, the siblings used the opportunity to murder most of the Mhuruuks (the magical priest class under Olnar's rule) and successfully sealed off the Mindless Ones from the rest of the populace. They secured rulership of the realm under the guise of heroes for ages. Later on Dormammu banished Umar after she gave birth to her daughter, Clea, in one of the pocket dimensions under his control, taking sole custody of the Dark Dimension.
In the 1978 movie, Dr. Strange, Dormammu was renamed the Nameless One.
- Dormammu was planned to appear in another episode had Spider-Man: The Animated Series been renewed for the sixth season. In that episode Mysterio would have been Dormammu's servant instead of Baron Mordo. Mysterio would have used the Time Dilation Accelerator to open a portal to our world and release Dormammu. Spider-Man would have then teamed up with Ghost Rider to defeat him.