Since his first appearance, Thanos has been a major player in the Marvel Universe

Thanos. The Mad Titan. Since his debut in 1973's "Iron Man" #55, he's played a major role throughout the Marvel Universe as one of the most powerful and cunning menaces the heroes of Earth have ever faced. Conqueror, death dealer and even unlikely universal savior, Thanos is an undeniably complex character with ever-changing motivations and inscrutable schemes. Now, after his surprise appearance in Marvel Studios' blockbuster "The Avengers," audiences are eager to learn what lies behind that fearsome purple visage, so we've decided to take a trip inside that warped mind and give you some insight into the motivations, goals and schemes of Marvel's top cosmic antagonist throughout the years.

Created by writer/artist Jim Starlin as part of a psychology class project, Thanos is based on the Freudian concept of "Thanatos", the "death instinct" human beings are said to possess which drives them to dangerous and destructive actions (Starlin also created Thanos' brother Eros, AKA Starfox, based on the Freudian "life instinct" concept, and The Destroyer, Thanos' archenemy, as the personification of anger). Thanatos also happens to be the name of the Greek deity personifying Death, and these connections are interwoven in the background that Starlin created for Thanos and his kin, as they were originally portrayed to be the offspring of the Greek Gods, though this was later revised to be a connection to Jack Kirby's Eternals.

Thanos' connection to Death is present from his earliest appearances in "Captain Marvel" #25-34, (following on from his "Iron Man" debut) where he is depicted as an alien warlord bent on the conquest of Earth and, eventually, the universe. The company he keeps sets him apart from your average alien warlord, however -- we frequently find him in the presence of a hooded woman who is revealed to be the Marvel Universe's personification of Death itself. Thanos is in love with her, and revels in the destruction that his wars of conquest bring, all so he can please his dark mistress.

But conquest is not enough for him; Thanos seeks the power of the Cosmic Cube -- known as the Tesseract in the Marvel Cinematic Universe -- in order to become a veritable god. He succeeds in his goal, but his own psychological flaws provide the key to his defeat. Thanos craves not just power, but the actual worship of those he rules over, leading him to make a critical mistake; he toys with his foes, seeking to impress them with displays of his sheer power, giving Captain Marvel and his allies the opportunity to destroy the Cube and end Thanos' bid for godhood.

Thanos survived the attempt, however, and next presented himself as an ally to Adam Warlock, who was at the time engaged in a struggle against, quite literally, himself. In a storyline running through "Strange Tales" #178-181, "Warlock" #9-11 and the 1977 "Avengers" and "Marvel Two-In One" Annuals, Thanos assisted Warlock in defeating the Magus, a tyrant from the far-flung future whom Warlock had discovered he would one day become. But this was no sudden change of heart for Thanos; rather, it was all part of a complex scheme to gain control of Warlock's Soul Gem, a powerful artifact with the ability to capture living beings' souls. Thanos discovered that it was just one of six such gems that, when combined, would give him power greater than even the Cosmic Cube, power that would enable him to offer his beloved Death the ultimate gift -- he planned to extinguish all the stars in the universe, thereby ending life as we know it. Warlock and the heroes of Earth confront him once again, putting a halt to his mad designs by transforming Thanos in near-lifeless stone, fated to hover throughout eternity on the edge of life and death -- but not before Thanos succeeds in bringing death to Warlock himself.

Thanos, in the thrall of the power of the Infinity Gems and also in a moment of calmness

Those stones, now known as the Infinity Gems, would play a major role in the Thanos' inevitable return during 1991's "Infinity Gauntlet" event, as played out in the pages of "Silver Surfer", the "Thanos Quest" miniseries and the "Infinity Gauntlet" miniseries. Mistress Death saw a major problem in the universe, one that could best be addressed by Thanos' unique talents -- there were more beings alive throughout the universe than had ever died, creating, in Death's view, a cosmic imbalance. Returned to the land of the living in order to deal with this issue, Thanos' solution was one very much in-keeping with his love of death -- he proposed to kill half of all living beings in the universe. To accomplish this, the mad Titan convinced his mistress of the necessity of re-acquiring the Infinity Gems, but Thanos had come to realize the Gems were not mere blunt instruments of destruction. Collectively, they offered control over all aspects of existence -- Soul, Mind, Time, Space, Power and Reality. With them, for the first time Thanos could become not merely a servant of Death, but Death's equal.

Utilizing his brilliant strategic mind, Thanos successfully outwitted some of the most powerful beings in the universe, stealing their Gems and assembling all six onto his gloved hand, forming a device that came to be known as the Infinity Gauntlet. True to his word, one of his first acts was to wipe out half the life in the universe in a blink of an eye -- on every world, including Earth, half the population simply disappeared, summoned to Death's realm at Thanos' behest. But this did not win Thanos Death's favor, as he'd dreamed -- Mistress Death was instead coldly furious with her former lackey's usurping of her position, and rejected his advances. His efforts did win him the attention of some of the universe's other most powerful beings, including Eternity, the personification of all existence. With the Infinity Gauntlet, Thanos was able to defeat them all and supplanted Eternity, taking his place as an abstract cosmic entity and leaving his physical form behind. As with his failed attempt with the Cosmic Cube however, Thanos once again made a crucial mistake, leaving the Infinity Gauntlet with his mortal body, enabling a resurrected Warlock to eventually seize control of the gems. Warlock, having been inside the Soul Gem, revealed to Thanos why it is he constantly makes these errors which result in his defeat -- subconsciously, Thanos does not believe himself worthy of winning. Rather than be captured upon his defeat Thanos appeared to commit suicide. Warlock realizes Thanos has fooled everyone, however, and instead seemingly choosing to give up his designs on power and live out his life as a simple farmer on a distant planet.

Drax the Destroyer fulfills his destiny, killing Thanos

But power and Thanos cannot be separated for long; as custodian of the Infinity Gems, Warlock is charged with dividing them up amongst protectors of his choosing, so no one being can ever claim absolute power. He assembles his "Infinity Watch," but the most powerful gem, the one controlling Reality, is given to a wielder whose identity he keeps a closely guarded secret -- because it is none other than Thanos. Even Warlock comes to question his own decision, but given that it was made at a time when he possessed omniscience, he concludes Thanos must be a trustworthy guardian. And for a time, Thanos does prove to be a responsible bearer of the power, even assisting the Infinity Watch during the "Infinity War" and "Infinity Crusade" events.

The gems were eventually lost to another universe, but that did not bring an end to Thanos' role as a prime player in universal events. During the "Infinity Abyss" miniseries, written and illustrated by Thanos' creator Jim Starlin, it was revealed that Thanos has created a series of clones of himself, called Thanosi, for purposes of experimentation. Some of these clones were flawed, explaining why in some of Thanos' appearances (specifically, those not written by his creator, Starlin) Thanos had at times seemed out of character. These flawed clones eventually posed a threat to the universe independent of their creator, forcing Thanos to seek the help of Adam Warlock in disposing of them. Having come to realize that his many acts of destruction would lead beings across the universe to seek vengeance upon him even if he had renounced his old ways, when Thanos discovered a new source of ultimate power -- the Heart of the Universe. Thanos considered the most prudent course of action to be to acquire it for himself, as told in the "Marvel Universe: The End" miniseries. Like his other bids for ultimate power, he once again did not prove ready for the position; even though he no longer sought universal destruction, Thanos could not manage the power he obtained, ultimately destroying the universe by accident. In perhaps the first true act of remorse in his life, Thanos, the ultimate nihilist, restored the universe to existence.

Continuing his quest for redemption, Thanos, now starring in his own series, set out to make amends for his past misdeeds, starting with the Rigellian species whom he'd brought death and destruction to in the past. He even rescued the world-devouring Galactus from an other-dimensional entity which threatened all of reality. However, in the "Annihilation" event, Thanos seemingly reverted to type, aiding the deadly Annihilus in his invasion of our dimension. It was soon revealed that Thanos was playing both sides for his own ends, but before his schemes could come to fruition, his old foe Drax The Destroyer finally achieved his life's goal -- killing Thanos.

Finding fulfillment in the arms of Death, which he'd sought for so long, Thanos' contentment was not to be permanent. His old ally Warlock came upon his corpse and enveloped it in a regenerative cocoon. Unwillingly, Thanos returned to the land of the living during "The Thanos Imperative" event, just in time to be thrust into a conflict with the Cancerverse, a universe where Death herself had been destroyed. The unkillable hordes of the Cancerverse were now invading the Marvel Universe, and the heroes known as the Guardians of the Galaxy saw Thanos, the ultimate Avatar of Death, as their sole chance to stop them. But Thanos, still holding a grudge over being returned to life, turned on his erstwhile allies, leading to a cataclysmic destruction of the Cancerverse along with -- seemingly -- the Guardians and Thanos himself.

Recent events in the pages of "Avengers Assemble" have once again called Thanos' ultimate fate into question, proving that as the rare being in the Marvel Universe with a literal on-again, off-again relationship with Death, one can never, ever count Thanos out.