The events of Infinity Guantlet – in which Marvel's heroes united to stop Thanos after he had gathered all the infinity gems — left the Infinity Gauntlet and its six Infinity Stones under the guardianship of Adam Warlock. Marvel's cosmic pantheon wasn't happy with this choice, however, and didn't think Warlock could handle such a responsibility, so Warlock chose five people to whom he gave the remaining gems. For himself, he kept the Soul gem.
In Warlock & the Infinity Watch #2, Warlock revealed the candidates for most of the other stones (with the exception of one — surprisingly, he entrusted Thanos with the reality gem). To Drax the Destroyer went the power stone, augmenting his already immense power. Warlock said he chose Drax because he would know better than most how to handle power.
Warlock would later question his decision-making, believing the power of the Infinity Gauntlet had corrupted his thinking. He gave the space gem to the mischievous Pip the Troll (who immediately used it to steal, among other things, an Avengers quinjet). He gave the mind stone to Moondragon, who had once used her powers to enslave an entire world. And of course he gave an infinity stone to Drax, who destroys things when he misses Alf.
Drax remained custodian of the power stone until it, along with the other stones, was stolen by the villain Rune.
