Synopsis
This issue begins with Sphinxor from Pegasus answering our question "Who is Adam Warlock?" as an excuse to recap his previous apps.
He was born as Him in Fantastic Four #66-67. 4 scientists called the Enclave in a secret lab called the Beehive created him to be the perfect future man. He emerged from a cocoon. But he detected that his fathers were evil, destroyed their base (although it turned out later that 3 of the 4 survived), and flew off into space.
In Thor #165-166 Him tried to claim Thor's girlfriend Sif as his mate, and of course had to fight Thor. He lost the battle and retreated into a cocoon again.
In Marvel Premiere #1 Roy Thomas took over from Lee&Kirby and turned Him into a very different char when the High Evolutionary (a Lee/Kirby creation from Thor) found the cocoon. HE had created Counter-Earth on the far side of the Sun, but created it free from evil. But earlier he had uplifted animals into his New Men, and a wolf became his arch-enemy the Man-Beast. While Herbert Edgar Wyndham accelerated the evolution of the new world, Man-Beast tainted it with evil. Now the Evolutionary woke Him and gave him a costume and a new name Adam Warlock. He also gave him a weapon, the Soul Gem on his brow, and sent him down on a mission to save Counter-Earth.
MPr#2 and Warlock #1-8 showed that mission as Warlock battled the plans of Man-Beast and his evil New Men with the aid of 4 teen followers.
The series ended but the story was concluded in Hulk #176-178. The story had begun on a Biblical note as HE created the Earth as a paradise which was then corrupted by the renegade Man-Beast. And HE sent down his 'son' Adam to save the world. But in this final section the theme was made even more overt as Warlock was effectively crucified but later returned from his cocoon. He then used the Soul Gem to revert Man-Beast and the evil New-Men back to animals. And then he left again for space.
Sphinxor now ceases his narration and we see where Adam Warlock is now.
A lightly-spacesuited girl runs from 3 pursuers across a barren planetoid and winds up at the feet of Warlock who it turns out she'd been seeking across 'a dozen galaxies'. (Apparently he's done a lot since we last saw him because he's famous). The hunters claim to be Grand Inquisitors from the Universal Church Of Truth and she is an infidel marked for termination. Our hero of course opposes them as they attack in the name of the Holy Magus. The most powerful is a Roclite (like the Blood Brothers that Jim Starlin introduced in his 1st Thanos story Iron Man #55) but the Soul Gem defeats him. However the others kill the girl and then the 3 teleport away.
Adam uses the Gem to bring the girl temporarily back to her dead body so she can tell him her story. She tells him of the Magus who appeared 5000 years ago and created the Church with himself as its God. It is now the most powerful force in the Galaxy under its temporal leader the Matriarch. It preaches peace and love but only for its own members. Its aim is to convert all to its faith, and any means are justified. Any 'heretics' like herself are executed. Any world which won't let them in is destroyed by the Purification Fleet.
But when he asks more about the Magus the girl is taken over by the God himself. As well as bragging about how powerful he is Magus hints that to understand *him* Adam should 1st understand himself. And he sends our hero into a dimension filled with demons that Warlock finds somehow familiar. Then Magus sends him deeper, eventually to a fractured mirror that shows both their faces and a death-skull. In the next hallucinatory scene Magus' taunts make Adam realise at last that the demons were his own inner demons, Magus is another word for Warlock, and the God is somehow himself. (Maybe an early clue was that the Church's symbol, seen only in 1 panel, was the same shape as the device on which Warlock was 'crucified'.)
Magus now releases him back to the planetoid where the girl has returned to death. And Warlock pledges to stop the Magus even if it means killing himself.