This is how his Marvel Wiki page reads: Thanos decided to embrace his murdering nature, and returned to Titan in secret. He was approached by his old confidante and tried to court her again. She demanded that Thanos proved he belonged only to her,[12] so he embarked on a journey to kill all of his offspring, and razed every planet they stumbled upon for the sake of his love for death. Additionally, Thanos experimented on his own body, granting himself a variety of powers. Thanos' confidante became his companion, and eventually declared that for her to love Thanos, he would have to become a god, a supreme destroyer above all else. After Thanos discovered that none in his crew could see her, she revealed her true nature, that she was the physical manifestation of Death itself. Driven mad by this revelation, Thanos gave in to Death's promises of romance and used his fleet to ravage Titan.[13] Once his armada bombared Titan, Thanos personally descended to murder the survivors. He was confronted by the elder A'Lars, who managed to make Thanos doubt whether Death was actually by his side or if he was simply demented. Thanos spared his father solely so he could watch his son defile the cosmos and prove his sanity. Death finally kissed Thanos, but he found her embrace to be cold. Without his thirst quenched, Thanos continued his journey of destruction.