A villain published by Marvel Comics
. Korvac first appeared Giant Sized Defenders #3
In the 1980's, DC Comics sought to deal with its issues with multiple realities during the Crisis on Infinite Earths, standardizing the history and events of the their reality. Admittedly it has taken them a couple of shots at it, but at least, DC has attempted to address the situation. Marvel Comics however has never taken a shot at it, instead staying satisfied with having multple histories and multiple futures all existing at the same time. The future in particular has many different potential outcomes. We had the "All-The Mutants-Get-Stuck-In-Camps-By-The-Sentinels" future. We have the "Apocalypse-Rules-The-World" future. We even have the "Lizard-Aliens-Take-Over-The-Earth" future. It is from this last future that Korvac comes.
Michael Korvac was born in the 31st century and after the Badoon, a race of reptilian humaniods, invaded and took over the Earth and wiping out most of the inhabitants of its colonies scattered around the solar system, Korvac was employed by them as technician. The Badoon are not the most understanding of bosses and when Korvac collapses after working non-stop for an extended period of time, the Badoon do not simply report him to the HR department and move on. Instead, they have the lower half of his body amputated and him grafted onto a computer terminal.
Korvac is needless to say miffed and uses his new-found link to computers to gain enough power to take the Badoon responsible off the corporate payroll permanently, if you get my drift. He then decides to use his computer half to tap into the Badoon computer network and set himself up as the new emporer. But before he could put his plan into action (which involved tying up the Badoon e-mail network with penis enlargement spam and a memo telling the all the departments of the Badoon government to load Windows ME on their computers), Korvac was plucked from his time and brought to the mid-70's by the Gamesmaster to fight the Defenders, which is sort of like being transported to the court of King Arthur and made to spend your time talking with Sir Kaye. Korvac fought the Defenders, but eventually stole enough power from the Gamesmaster to return himself to his own time.
Upon returning to his native time, Korvac recruited a group of varied powered aliens (which is requirement if you are going to fight a team of heroes in an Marvel annual) and battled the Guardians of the Galaxy along with the Norse god Thor who had been transported 11 centuries into the future. Korvac and his minions were defeated, but Korvac managed to escape and traveled back to the 20th century.
Despite the obvious fact Korvac could have bought the galaxy off the temporal frequent flyer points that he was earning from all of this time travel, he continued to seek power and found it in the form of Galactus's world ship. Like Doctor Doom in the Secret War years later, Korvac tapped into the power of the ship and grew to god-like status. He reformed his body to one of perfection and decided that the universe could use better management and elected himself for the position. Korvac settled down and began to plot his take-over of the universe all the while calling himself Michael. While he lived in human form, he fell in love with a woman named Carina, who was actually spying on him. Carina was the daughter the Elder of the Universe the Collector who was concerned about what Korvac/Michael had planned.
Meanwhile, the Guardians of the Galaxy traveled back to the 20th Century to stop Korvac. They contacted the Avengers and the two groups began to hunt for Korvac. But one of their number, the enigmatic Starhawk used his heightened perception to track down Korvac and confront him. Using his god-like powers, Korvac utterly destroyed Starhawk, but then realized that this would alert the heroes, so he resurrected Starhawk, but with the difference that he made himself undetectable to the new Starhawk.
The Collector began to panic at the threat he perceived Korvac to be, so he began to kidnap or "collect" the members of the Avengers in hopes of using them to defend him against Korvac. Those Avengers that had not been collected tracked their comrades to the Collectors hide-out and freed them. The Collector was preparing to tell the Avengers of his reason for capturing them, when Korvac vaporized him with an energy beam from a remote location. The Avengers tracked the energy beam back and discovered a man named Michael at the other end of it. Puzzled, the Avengers along with the Guardians were prepared to chalk it up to a mistake, when they realized that Starhawk was unable to detect the presence of anyone there. A fight ensued in which most of the Avengers and Guardians were killed by Korvac. As he fought, he looked to Carina for support and found that she hesitated and looked doubtful. In one of the biggest cases of over-reaction on record, Korvac decided that her hesitation meant that his taking over the universe was pointless without her love, and committed suicide, rather than just dusting her and recreating a new Carina that never hesitated. As a final act of compassion, Korvac returned the heroes to life.
Korvac's life was not at an end however. His essence traveled into his ancestors and began to be passed from generation to generation in a plan that Korvac believed would allow him to have his power from the beginning of his life which would allow him to fix the issues that brought about his defeat. The Guardians of the Galaxy (who are also part of the the Tempus Airlines frequent time travel club) pursued Korvac's essence, finally preventing Korvac completing his plan.