Synopsis
In Strange Tales #178 Adam Warlock met a woman fleeing from Grand Inquisitors of the Universal Church of Truth. He failed to stop them killing her but used his Soul Gem to get her soul to tell him what's going on. She said that the Magus founded the Church 5000 years ago and set himself up as its god. The Church is run by the Matriarch and has spread by force to most of the Galaxy. But the Magus interrupted their discussion and revealed to Warlock that they are the same person.
In #179 Warlock was captured by Black Knights led by Captain Autolycus and placed in his slave ship. Magus wanted Warlock alive but the Matriarch figured killing Warlock might destroy Magus and leave her in sole control. Autolycus thought it dishonourable but must obey. Warlock helped the slaves revolt, and Autolycus' soul was consumed by the Soul Gem. When Adam left he was accompanied by Pip the Troll.
In #180 Adam (with a new cloaked costume) and Pip arrived on the Church's Homeworld. Warlock tried to remove his vampiric Soul Gem but discovered he now needed it to survive. Matriarch invited him to a meeting and told him Magus was his future self. Then she sent him to a mock trial before Grand Inquisitor Kray-Tor. Warlock was found guilty but he allowed his gem to steal the judge's soul. But he was then tormented by Kray-Tor's belief that *he* was in the right. Meanwhile Pip was met by a green woman who said she'd come to help Warlock or kill him.
In #181 Matriarch's technicians were trying to reprogram Warlock's mind. Meanwhile Pip was heading to the rescue with the green woman who turned out to be Gamora, known as the Deadliest Woman in the Galaxy. They reached their goal just as Adam broke free by defeating the Madness in his own soul. But then they finally met Magus, a purple guy in a purple version of Warlock's old costume.
Now Magus easily repels Warlock's attack with *his* Soul Gem. He says that Order and Chaos have ordained the Adam will become him. And to prove he is Warlock's future version he repeats Adam's long-winded reply from memory as he says it. Magus gives Warlock a potted summary of his actions in ST and claims this was all part of his plan to mess with Adam's mind as a preparation for the upcoming transformation into himself.
Pip asks Gamora to save Warlock but she says now is not the time, and gives him a weapon instead. Pip charges in and Magus casually knocks him out. Now the villain says he and Adam are alone, which is just what she wanted to hear. She telepathically contacts her master to confirm that Magus is unaware of her as predicted. The master tells her to strike at the time they agreed.
Meanwhile Magus goes into explain-my-masterplan mode. He says that when Warlock attacks him after this chat he will use *his* Soul Gem to imbue Adam's body with a radiation which will guide to him the In-Betweener. No matter how Warlock tries to escape the In-Betweener will find him 3 hours later, and his touch will take Adam into his own realm where centuries of whispered 'dark secrets' will erode his certainties about good and evil. He will retreat into the cocoon that birthed him (in Fantastic Four #67) and emerge as Magus.
Magus will find himself 5000 years in the past on Homeworld. He will have regained the Him-level of power Warlock lost in a previous cocoon sojourn (Marvel Premiere #1) which enables him to set himself up as God of Homeworld. He will then create the Universal Church of Truth and send his Black Knights and Grand Inquisitors on a holy war to 'convert' more than 1000 other planets. 4 years ago he began to create the scenario he remembered here by raising up a particular prostitute as the Matriarch.
As predicted Warlock has recovered and attacks, and Magus strikes back with his Soul Gem. But this isn't the predicted radiation bath. Magus has a few minutes left to play with his victim, so he chases Adam through a twisted reality that he causes. Pip and Gamora are also trapped in this reality but she has been trained for this moment to cope with the distortions. And Magus' senses refuse to accept her presence that isn't in his memory.
As Magus counts down the last seconds to the appointed moment Gamora sneaks up behind him, and tries to stab him just as he is about to do the radiation thing. But he strikes backwards to hit her even as he uses the Soul Gem for the 'fatal' blow.
Magus explains that his astral senses actually penetrated Gamora's 'multi-actual' camouflage, so she should return to her master and tell him that Magus will be after *him* next. And he leaves with unruffled confidence while Adam Warlock bewails his fate. On Counter-Earth he really was a saviour. But now his vampiric Soul Gem has stolen the souls of Autolycus and Kray-Tor, and he is destined to become an evil god.
Meanwhile Magus' henchmen have arrested the Matriarch for treason and Magus drops her through a trapdoor to become a 'martyr who died defending him against Warlock'. He sends General Egeus with 2500 Black Knights to kill Warlock and those with him. He doesn't expect them to succeed but it will keep Adam busy until the In-Betweener arrives.
But in that room Gamora's master Thanos enters through a portal to take personal command of the situation.