From Marvel Comics: The Untold Story:
Roy Thomas had made the Warlock character a Christ figure; now Jim Starlin, the recovering Catholic, used him to deliver a critique of organized religion, as well as a protest against systemized stiflings of creative voices.
Wandering space, Adam Warlock comes upon a “non-believer” who’s being pursued by armed soldiers; he tries to save her, but fails. Using the “dread power” of his mysterious Soul Gem, he revives her just long enough to learn that her killers were from the Universal Church of Truth, an iron-fisted group with intergalactic reach, led by a being called the Magus—who, Warlock is shocked to learn, is his own future self.
As Warlock journeys to find the Magus, he gains unlikely allies (the foulmouthed troll Pip; the green-skinned, fishnet-wearing alien assassin Gamora) and several more enemies (including Captain Marvel’s old foe Thanos). But the greatest threat to his survival, and to his sanity, is the powerful crystal on his forehead—the vampiric Soul Gem—which, he slowly realizes, is thirstily absorbing the spirits of his enemies.
Adam Warlock’s adventures were perfect vehicles for Starlin’s meditations on the price of power, and for the suspicions he harbored toward rigid institutionalism. Plotting, scripting, penciling, inking, and coloring, Starlin was, in a sense, the first auteur that Marvel had seen since Jim Steranko’s early carte blanche days.