Immortus is said to be the final incarnation of Kang the Conqueror . Immortus was born on Earth sometime in the 31st century. This is an alternate future from the Guardians of the Galaxy; in Immortus' reality, the Badoon never conquered Earth. After pillaging the time stream using his technological powers to subjugate different time periods, he settled into the role of Rama-Tut.
As Rama-Tut, he at one point captured the Fantastic Four and attempted to marry Sue Richards, the Invisible Woman. Curiously, it was later revealed that Immortus is a descendant of his namesake, Nathaniel Richards, father of Mr. Fantastic making the Invisible Woman a great aunt, many times removed, to Immortus/Kang/Rama-Tut.
Immortus was created by Stan Lee and Don Heck in 1964 and first appeared in The Avengers # 10.
After further adventures as both a despot and a benevolent ruler, an older and more philosophical Rama-Tut travelled to Limbo to finish his remaining years. However, the Time Keepers approached Rama-Tut and offered him immortality in return for serving them as guardian of part of the timestream, covering 80 millenia.
At this point, he became Immortus and worked to repair the damage that he and his other incarnations had done to the time stream. He maneuvered through the timestream, focused on preventing time paradoxes and eliminated unnecessary time travelers, such as when he removed Mjolnir's time traveling ability with Thor's permission.
When the Time Keepers got aware of some possible futures where the Avengers had left a legacy that would be an universal dictatorship, they tasked Immortus to prevent this future from ever happening. Immortus started a long-term plan of manipulating the Avengers as well as others and various events in their history, only to later realize that he accidentally created the very future he was supposed to prevent. Afraid of the Time Keepers destroying the world and the Avengers, Immortus asked for one final attempt. In order to do this, he planned to kill Rick Jones in order to prevent him for releasing the Destiny Force. However, this plan was endangered when his younger self, Kang, who had heard of the Time Keepers' plans, saved Rick and summoned the Avengers for helping him in his war against Immortus.
Immortus was able to invade Chronopolis with his army and use it's power source to create the Forever Crystal, which he used to influence various events, like creating two versions of the original Human Torch with one of them dying, the other one becoming the android known as Vision. He also tried to prevent humanity from ever reaching into space by further manipulations, like revealing a Skrull disguised as President Nixon to the crowd as he would've later be discovered and his revelation would cause humanity to fight aliens, which would eventually result in the tyrannic Avengers. Immortus allied himself with Yellowjacket, who promised him to lead him to the Avengers in return for remaining in a time-line where would never turn back into Hank Pym and live happily with Wasp. The two took the Avengers by surprise and led them to a trial held by the Time Keepers, who revealed their intentions of using the Forever Crystal to destroy humanity. Immortus pleaded to contain humanity instead of destroying it by using the Avengers as guards, but the Time Keepers denied this plead as it would be the Avengers who would eventually lead to the intergalactic tyranny. When Yellowjacket restored the destiny force back to the Avengers, the Time Keepers and Immortus fled, but with Kang's help, they followed them.
The Time Keepers ordered Immortus to use the Forever Crystal to destroy them, but he refused due to his admiration for the Avengers, which resulted in the Time Keepers killing him and using the Crystal to summon all Avengers from every time-line where they became evil. They also decided to turn Kang into Immortus in order to stop the threat he was posing now as well as ensuring Immortus' past actions. However, Kang's refusal to become Immortus, which had been his main reason for fighting them all along, caused a backlash that weakened the Time Keepers, who were quickly killed by Kang. Kang tried to get his hands on the Forever Crystal, but Captain America got it first and smashed it. It was then revealed by Libra that the backlash also caused the transforming Kang to split up into both Kang and Immortus, the latter bidding farewell to the Avengers and his younger/alternate self after telling them that the crystal wasn't truly gone and would reappear eventually. After he left, Kang burst into laughter as now that a split version of him had become Immortus, it meant that he didn't have to.
Avengers Heroic Age
He continues in his role currently, working towards the higher purpose of keeping the timestream intact, though often using deception or murder. He does not care about morality as much in his role and uses others to further his personal goals - as was the case when he employed the Protectorate to eliminate the threat of the Dire Wraiths. Recently, in a shocking twist of fate, Immortus was murdered by the Next Avengers, before he died he claimed that he would be there to watch them die. What he meant by this is unclear.
Powers & Abilities
Immortus is immortal as a result of his service to the Time-Keepers. The Time-Keepers also appear to have granted Immortus control over time as well, though not to the degree of Kronos. Other abilities he has displayed in the past, such as energy projection or mental manipulation, may or may not be powers he has himself. Quite possibly these powers actually derive from technology he gained during his time travels.
X-Men: The Animated Series (1997)
During the foourth-parter "Beyond Good and Evil", Bishop encountered a seemingly crazy man called Bender while being trapped at the Axis of Time, which Bender claimed to be the creator of (at least that's what he thinks), spending most time as the janitor. The Axis was currently used by Apocalypse, who, with the aid of Mr. Sinister, Magneto, Sabretooth and Mystique, had been kidnapping various mutants with thelepathic abilities in order to destroy the universe by destroying them, as he claimed that "time is motion, and motion and thougt are unity.". After Apocalypse being defeated in the end and all the others returning home, Bender was left commenting about the mess that they caused before revealing himself to be Immortus in disguise.