Synopsis
This issue begins 200,000 years ago with the last battle before the Titan Schism, with Eternals fighting each other with advanced tech and dinosaur horses.
And then it pulls back for a brief Eternals' chronology:-
1,000,000 years ago the 1st (Celestial) Host.
600,000 years ago the Uranite Heresy.
500,000 years ago the Ascension Of Kronos.
200,000 years ago the Titan Schism.
1 year ago the Final Host (at the beginning of the current Avengers run).
Now the Thanosian Terror (in the current Eternals series).
Plus we get a description of the cause of the Schism:-
The Eternals were created by the Celestials, not by sexual reproduction, but they were created organised into 'families'. They can't breed with each other but they can interbreed with other human species. However their enhanced Nephilite offspring aren't true Eternals and aren't resurrected by the Great Machine.
The 'brothers' A'Lars and Zuras argued about A'Lars' desire to find a way to give the Eternals species true reproduction. Factions formed around them which led to the war above.
Back in the civil war Ikaris, Phastos and Thena are in A'Lars' gang. Ikaris joins the others with news that the Zurasians have found where the A'Larsites are resurrecting and are re-killing them. He himself died 7 times before he managed to escape. A'Lars orders the Machine to do randomly-placed resurrecting. He complains that he hasn't got anywhere with his research, and the war isn't helping.
But then Thena notices something on Ikaris' back, which expands into Sprite of the opposing side who claims to be a messenger (so probably Ikaris was *allowed* to escape). Sprite gives his reason for supporting Zuras:- The Eternals created him as the only teenage Eternal which is where he's stuck. He doesn't see why the others should get to change their nature if he can't. But anyway his message is that A'Lars' 'mother' Daina wants to broker a truce.
Daina, 'wife' of Kronos, holds the meeting on 2 paired molecules of her creation and asks her 'sons' to state their positions. Zuras says his 'father' and 'uncles' all failed in their visionary schemes. Uranos tried to conquer the humans, causing an earlier civil war. Kronos nearly destroyed the world in the process of making himself a god. Oceanus feared what he himself might do and retired to keep watch on the Deviants leaving A'Lars and Zuras in charge. Now A'Lars has brought war again. A'Lars retorts that their family relationships are lies, but Zuras maintains that Eternals families don't have to be like mortal ones. A'Lars of course says they *could* be. Daina chides them for rehashing old arguments (but isn't that what she asked them to do?).
The Machine now gives us a summary of the key arguments, which I will condense even further.
Eternals can create Nephilites. But they aren't Eternals.
Some Eternals are Excluded from resurrection and there should be a way to replace them. Their Exclusion is not necessarily permanent.
The Eternals' gestalt Uni-Mind made Zuras leader and now he just wants to maintain the status quo. Rubbish.
The space gods created the Eternals incapable of procreating amongst themselves. But this doesn't mean they would object to that being changed.
They created the Eternals to protect the Machine/Earth/humans. Maybe new Eternals will protect it better.
Eternals relationships, whether familial or friendship, last so much longer than those of mortals, and so are deeper. Humbug. Fight.
Daina tells them that her Gaian Sisterhood predict that Zuras will eventually win but at the cost of many Eternals being Excluded. And while the war rages A'Lars won't be able to complete his research. So she suggests a solution that has worked before:- A'Lars will go into exile to pursue his experiments. Most Eternals will have the conflict wiped from their memories by resurrection. They sort of agree. And so it goes.
A'Lars and Zuras of course remember. A'lars is going alone but he tells his brother that he will create followers by means such as cloning while he works on his true goal. Zuras asks who he will seek as a lover for the 'process' - the long-missing Ora or O-XX? A'Lars replies that there is a living Uranite he can contact. Daina warns her son to remember what happened to his father Kronos - banished to the Exclusion but also a disembodied spirit at large in the cosmos. (The Machine correctly reckons that she was hinting that he seek his father's help.)
A'lars takes the name Mentor and finds the Uranite Sui-San in the ruins on Titan. She is suspicious because Uranos and the surviving Uranites fled to space to escape Eternals' justice. He reminds her that all but she eventually died and were resurrected back on Earth where they were mind-wiped, except Uranos who was Excluded. He tells her that the others are mostly part of the Oceanic Watch monitoring the Deviants. She tells him that she only joined the Uranites to be with her lover, but that love died. Mentor offers her the possibility of love again, but in the meantime to help build a new civilisation on Titan.
They populate the place with "aliens, clones and constructs". Mentor and Sui-San *do* fall in love but fail to produce a child. Mentor calls on Kronos for help. He thinks it is a mistake but he fashions 2 Quantum Rings for them that will allow the impossible to happen. He leads them to Eon for a cosmic marriage ceremony where they don the rings, and Kronos predicts a boy. Sui-San suggests Eros for his name, symbolising their love. But Mentor favours Thanos, symbolising their triumph over death. She agrees.
Thanos is born, but he seems more like a Deviant than an Eternal. Sui-San can't love him and goes insane. Years later young Thanos murders her, and she is resurrected in the Exclusion. Mentor takes the Quantum Rings and throws them back at Kronos, who promises that they will always be used to oppose Thanos.
Later still Thanos kills his father too, and he too is resurrected. Ikaris and Thena pronounce his experiment obviously unsuccessful and he is to be Excluded. They tell him that he and his wife are Excluded because they might (or might be forced to) produce another such abomination. Ikaris says Sui-San doesn't want to see him - she wishes they had never existed.
A'Lars is given a special cell. It's dark walls will be populated by pixels counting the increasing deaths caused by Thanos. Very quickly the walls become a blaze of light which burns his eyes out.
The Machine is concerned about Thanos ever learning that Sui-San lives. Due to the automatic resurrection his desire to destroy the womb that bore him could only be achieved by destroying the Machine, and hence the Earth. (And that concern may bear fruit in the main series.)