Thanos was a genocidal warlord from Titan, whose objective was to bring stability to the universe by wiping out half of all life at every level, as he believed its massive population would inevitably use up the universe's entire supply of resources and perish. To complete this goal, Thanos set about hunting down all the Infinity Stones, being confident that the combined force of the Stones would grant him sufficient power. Thanos forged alliances with Loki and Ronan the Accuser in order to track down some of the Stones. However, both alliances cost Thanos much of his resources, including the Mind Stone and the loyalty of his daughters, Gamora and Nebula. Fed up with all his subordinates' ongoing failures, Thanos made the decision to seek and procure the Stones himself, and he began by forcing Eitri to create the Infinity Gauntlet for him so that he would be able to wield the power of the Stones safely. Thanos then engaged in a ferocious crusade in order to obtain the Infinity Stones. During his mission, both Thanos and his Black Order invaded multiple planets and slaughtered thousands to gain the stones, including Loki and the Asgardians. This quest even forced Thanos to sacrifice his beloved Gamora, in order to take the Soul Stone. Thanos soon found himself challenged by the alliances of the entire universe's greatest heroes, which included the Avengers and Guardians of the Galaxy. However, despite facing off against the powerfully combined opposition and the wrath of Thor, Thanos still ultimately triumphed as he completed the Infinity Gauntlet, using it to finally complete his goal through the Snap, which resulted in half of all life in the universe being wiped out with a mere snap of his fingers. Following his Snap, Thanos had then ensured this could never be undone by destroying all of the Infinity Stones, resulting in the Avengers tracking him down on Planet 0259-S, where Thor executed him with Stormbreaker. Thanos was usually seen by everyone else as the ultimate personification of sadism, cruelty, megalomania, infinite destruction, death, power, and madness, with his search for the Infinity Stones seen by others as his plot to gain dominion over all the civilizations in the universe. In reality, Thanos was a more complex and tortured soul given that his traumatic past and obsession with completing what he perceived as his destiny had led him to commit horrible actions all in the name of saving the universe even at a great personal sacrifice to himself. He desired to use the Tesseract to look beyond the known worlds to find greater ones that it would unveil. He was also relentless, as seen by his gathering of children from across the galaxy to take as his own so he can raise them as assassins and aid him by tirelessly searching for the Infinity Stones. In addition to this, Thanos had extraordinary willpower, as evidenced by his absolute refusal to succumb to Mantis' sleep-inducing touch despite its ability to usually make her victims docile almost instantly through but a simple touch, with her thus remarking that the Titan was "very strong" in his mental fortitude. He was extremely intimidating and often unforgiving of failures. The Other once warned Loki that he would know a new kind of pain if he did not give them the Tesseract; this was proven true when he ruthlessly murdered Loki for his failure in retrieving the Tesseract for him and when he tried to kill Thanos. Even though Ebony Maw had never failed Thanos, he still feared his master and father enough that he did not dare go to Titan without having fully taken the Time Stone from Doctor Strange. Thanos threatened Ronan the Accuser that he would bathe the starways in his blood if he failed to deliver the Orb, visibly terrifying Ronan. He even forbade Gamora from rescuing Nebula when the latter fell into a trap whilst on a mission in the Cloud Tombs of Praxius. He had little to no regard for his subordinates, as seen by him showing absolutely no empathy when Ronan killed The Other. Regardless of his disregard for his minions, Thanos was shown to be an extremely skilled and charismatic leader, having been able to inspire fierce loyalty from the Black Order, as well as command the Chitauri and the Outriders, both being highly savage and powerful creatures, unchallenged. He was extremely confident to the point of arrogance and appeared almost impossible to intimidate, smiling when The Other told him challenging the Avengers would be like courting Death. He was even unfazed at the idea of Ronan, who was strengthened by the Power Stone, coming after him despite knowing full well that Ronan was already very powerful even without the Stone and the fact that he was backed up by Nebula who had betrayed him, displaying only anger. He also smiled confidently after deciding to hunt for the Infinity Stones himself. He was also manipulative and mistrustful, sending Ronan to retrieve the Orb for him and not telling him that it contained an Infinity Stone, while also sending Nebula and Gamora to monitor him. He is surprisingly patient, as he kept a low profile, lurking in the shadows and making others do his work for him even after centuries of failure. He did not make a move for the Infinity Stones directly nor did he openly show that he possessed an Infinity Stone until he was finally ready to collect the stones himself in rapid succession, presumably because he knew possessing one or more of the Infinity Stones would draw unwanted attention, prompting others to attack him and impede his preparations before he was finally ready. Thanos' actions, despite their brutality, were so low that even Doctor Strange, who kept a watchlist of beings that may be a threat to Earth had never heard of Thanos, before Dr. Banner told him who the former was. Despite Thanos' ruthlessness during the early days of his conquest, he was not without compassion, especially when it came to children. When he met the young Gamora during his invasion of her planet, in stark contrast to the claims of Gamora that Thanos killed her parents in front of her, he gently kept her from being a part of the random genocide of her people by giving her the task of balancing a blade he gave her and when her attention turned to her people's screaming, he gently reminded her to remain focused on her task. He especially loved Gamora, calling her his "favorite daughter"; he even hoped that she would be the one to inherit his throne, in spite of her repeated proclamations of hatred, forgave her treachery of not telling him the location of the Soul Stone and allowed her to keep the façade for years before finally deciding to retrieve the Infinity Stones himself and openly made it clear to Ronan that costing him Gamora as being one of the reasons he was angry with him. However, though he showed genuine love and care towards Gamora, Thanos was ruthlessly strict and feared by the rest of his children, as he was the one who had turned Nebula into a cyborg, and Ebony Maw feared his judgment should he fail. When he finally captured Gamora, Thanos treated her more like a guest than a prisoner. He gave her food and remained patient and appealing despite Gamora's anger, and rather than torturing her for the location of the Soul Stone, he instead had Nebula tortured to make Gamora tell him. He took the lead when they ventured to the Soul Stone's shrine and when they encountered the Red Skull. Not knowing if he was friend or foe, Thanos made a gesture telling her to stay back, shielding her with his own body. He was utterly heartbroken when it was revealed to him that he had to kill Gamora to gain the power of the Soul Stone, to the point where he shed tears and sincerely apologized. Although Thanos still went through with Gamora's sacrifice, as he believed collecting the stones was for the greater good, Mantis sensed his pain. When Gamora, upon seeing his victory from the future Nebula's memories, asked what did he do to the Avengers, rather than suspecting her or reprimanding her for not praising and relishing his victory, Thanos merely told her the truth and affectionately cradled his favored daughter's chin as he proudly proclaimed his victory. Even with all his strictness towards Nebula, Thanos showed that he did feel affection for her, as when Nebula swore to make him proud, Thanos was visibly pleased and encouraged her to do so. Although his lack of hesitation in torturing her to make Gamora confess the location of the Soul Stone could be another act of favoritism, Thanos did not actually kill her and in the final moments of his life, following Nebula defending his honor, Thanos genuinely thanked her and regretfully acknowledged that he'd been too harsh on her. When his past self saw this recording, he took those words to heart and decided to treat Nebula better, as evidenced by his breaking the chain Ebony Maw had wrapped around her neck and cradling her chin in his hands affectionately, believing her loyalty and giving her the chance to prove it by bringing him to the future, even though Nebula could have been freed of him in the future had she decided to betray him. He also trusted her to retrieve the stones herself and seemed very concerned when she wasn't answering her comm. When he learned from Doctor Strange that Ebony Maw was dead, he stated that the quest for the Infinity Stones "extracts a heavy toll" and with the loss of all his children and his followers, he mournfully acknowledged to Gamora's spirit he lost everything by fulfilling his goal. His love for his children was particularly returned by his Black Order children and even Gamora and Nebula did reciprocate his love to an extent, with Gamora breaking into tears once she'd thought she'd killed him and Nebula silently crying for Thanos once Thor had killed him, even closing his eyes so he could rest in peace. Thanos loved his race unconditionally and desperately sought to save them, going as far as to propose wiping out half of his kind so the other half may survive. His plan for saving his homeworld was rejected, leading to the fall of his race. This incident has burdened Thanos with immense regrets and remorse as he confessed to Gamora that he had ignored the inevitable extinction of his people once when he could have saved them by being more forceful and resolved in carrying out the genocide against his people's wishes. As a result, Thanos became more determined in exterminating half of the population of every planet to save these civilizations from the same overpopulation tragedy on Titan. This is why Thanos truly believes his cause for killing off half of everyone on all planets to be a righteous cause, seeing himself as a righteous soul who is doing what is necessary to save all the civilizations of the universe. As such, he stated that the Zehoberei did not suffer from environmental hazards, global hunger, or any other form of violence anymore, due to him killing off half of their population. Regardless of his campaign to murder trillions, Thanos' viewpoint of killing them in an admittedly painless and quick manner of disintegration was, according to him, mercy compared to all of life suffering the same fate of starvation that his people endured. Not only that, but he did make an effort to keep the casualty count to an absolute minimum during his quest for the Infinity Stones and let the Snap handle killing half of all sentient life. Though he sought the Infinity Stones, the most powerful artifacts in the universe, Thanos did not do this for selfish reasons, only seeing the Stones as a means to facilitate his goal of balancing the universe, even quick to destroy the stones to avoid being tempted by their power. He reserved special respect and even some empathy for those who displayed signs of great selflessness and bravery even if they were his enemies, as shown by how he praised Iron Man for bravely confronting him and wished the people of Earth would remember his heroism, complimented Star-Lord for being willing to kill Gamora, even stating that he "liked him" for his willingness to sacrifice his love for the universe, and briefly comforted Scarlet Witch after she destroyed Vision and the Mind Stone despite how crucial the last Infinity Stone was to his plans. By contrast, Thanos disliked those who sought power for selfish gain, holding Ronan's grudge against the Xandarians in contempt, openly expressing disgust of Collector for his value of possessing over all else in his illusion, and showing outright disapproval that Thor wanted to gloat at him and didn't kill him instantly as he could have. Thanos had shown a dark sense of sarcastic humor and was able to remain calm and unfazed in situations that would frighten and shock most others, as he remained fully composed even after thwarting Loki's assassination and mocked him for choosing the word "undying." He ignored Loki's acts of defiance before dying, with Loki declaring he would never be a god as he was suffocated. He even remained unfazed after being badly injured by Thor and even mocked him for not striking him in the head. Thanos had also shown himself to be surprisingly honorable. He did not go back on the end of the deal he made with others and would honor them even when angered, as he was still willing to destroy Xandar for Ronan should he retrieve the Orb even though he was angry at Ronan for coming to him empty-handed and alienating Gamora. He extends this even to his enemies, as he did not kill Iron Man after acquiring the Time Stone as he promised to Doctor Strange and instead simply left Titan. Despite his manipulative nature, Thanos is also known as a man who never lies, a fact firmly confirmed by his own daughter Nebula and further shown by how Thanos showed genuine disappointment at Gamora's lie, stating that out of the many things he taught her to, lying was never one of them. Although he may play favorites with his children based on their skill, he also proved to be fair when it came to judging their loyalty. When he saw what seemed like a betrayal in the 2014 Nebula, rather than immediately kill her, he brought her to his ship to thoroughly investigate her memory. Interestingly, despite being regarded by many as an incredibly cruel and cunning being, Thanos did not take his genocidal motives as a pretext to eliminate potential foes who could be able to exact revenge on him. Indeed, he kept his intent to make his genocide as random and dispassionate as he intended, resulting in the survival of several members of the Avengers and the Guardians of the Galaxy who had done everything they could to stop him. Although he did destroy the Infinity Stones to prevent any chances from undoing his actions, with his victory seemingly ultimately fully secured, despite knowing fully well his surviving enemies would come for him to get revenge, Thanos did not attempt to avert what he knew would be his death by their hands, not bothering to create defenses or even fighting back at all, and allowed himself to be at their mercy and accepted his fate with dignity. It was only after another version of himself was confronted by these survivors did Thanos realize that there would always be people who would seek to undo his actions, prompting him to extend his plans from balancing the universe to simply erasing it all and creating a new one. Between 2014 and 2018, Thanos became more mellow. An example of this was when he referred to the Avengers as "unruly wretches" in 2014, while in 2018, he expressed his respect for Iron Man and did not refer to his enemies with derogatory terms, even referring to Scarlet Witch as "my child" when empathizing with her about losing a loved one. When he completed his task and retired, Thanos became even more mellow. When Nebula defended him by saying he is not known for lying, Thanos thanked her and expressed regret at treating her too harshly.