The Pantheon Series
In the late Pleistocene era, an alien modifies two primitive humans with nanotechnology granting them effective immortality, before unexpectedly having to abandon them alone on his spaceship. They and their descendents go on to become the inspiration behind the various pantheons of ancient Earth mythologies. Those first two, Keie and Oron, have twelve children, and their youngest son, Kron, with the help of four of his five brothers, eventually overthrows Oron and usurps control over the group and the spaceship they live on. Fearing being overthrown by his own children, Kron has them imprisoned on the ship; but with Keie's help, Kron's wife Rhea hides their youngest son, Xio, on Earth, where he is raised among humans. When Xio comes of age, he is returned by Keie to the ship, which sparks a long-brewing revolution against Kron, lead primarily by the eldest of the third generation, firstborn daughter of the eldest and only son not to turn against Oron: Met. During that revolution the ship is crashed into the Pacific ocean, but Kron is thrown from it on the way down, presumably to his death, while his four loyal brothers are locked within the ship as it sinks. The rest of the family swim ashore to a continent in the South Pacific that is today submerged beneath what we know as New Zealand, a land they call Auei, where they come to be worshipped as a pantheon of gods by the primitive humans there, ruled over now by Xio and Met. Using their advanced knowledge from the alien databanks on the ship, they intend to build this isolated group of humans into a spacefaring civilization and then leave Earth again. They have offspring with these humans, and two of those offspring, a male and female, are offered access to the genetically engineered food that their immortality-granting nanites require, making them immortal as well. Those two become the king and queen regent, the proxy rulers, of the human civilization the Pantheon are building, and under their rule a relative paradise, by pre-agricultural standards, is quickly built. But Kron turns out to have survived the fall — he is immortal after all — and out of spite he seduces the queen-regent of that paradise into war against the other human tribes beyond it, and she in turn convinces the king-regent to follow after her, leading their country to the start of war. For their digressions, the Pantheon banish the regents from their paradise, and appoint the second of their two sons to the throne. Angered by this, and by the banishment of their parents, the first son kills the new regent, inciting a civil war within the country. The Pantheon intervene again to banish that elder brother and all his followers out into the eastern sea on primitive boats, to find other lands and trouble Auei no more, while the third and youngest brother is appointed the new regent. Back on track at last, the Pantheon and their human civilization finally start developing at a reasonable pace toward the development of the space elevator that is their ultimate purpose, but that plan is ultimately dashed entirely when the Pleistocene ice age ends, and sea levels begin rising far too rapidly to compensate for, inundating almost the entirety of Auei. The Pantheon flee north to southern Asia in one boat, while part of their regents' family (those who aren't trying to save the rest of their civilization from the floods) take a second boat that is separated at sea and thought lost, though unbeknownst to the Pantheon it eventually makes its way across the Indian Ocean to the shores of the middle east. (More details).
The Pantheon wander south Asia looking for a place to start again, settling on the Indus River Valley. While they try once more to restart their project to escape Earth, a rift begins to develop between them. One faction thinks they should stick to the mission given to Keie and Oron, to watch and observe humanity and not interfere, noting that their isolated project on a small remote continent was very different from what they're doing now here in the middle of the largest continent, where they should at most be teachers, mentors, or guides, not rulers, judges, and masters. The other faction has no problem taking up the mantle of godhood that the primitive savages thrust upon them, and using said savages to speed their escape from this undeveloped rock they're stuck on. The Pantheon turn to Xio and Met to settle the matter, but their leadership is soon shattered, thanks again to interference from Kron. Met has become pregnant by Xio, and Kron counsels him that just as Kron overthrew Oron and Xio overthew Kron, so too this child will overthrow Xio; Oron, lost in space (thanks to Kron) but capable of telepathic communication through their nanites, concurs. With great reluctance, Xio concedes and agrees to a plan to prevent that fate, using a psychic ability granted to him by Oron to strip Met's mind out of her own body and into his mind, so that her body may die and their child with it, but they can be together forever. Met is understandably furious at this action, and from inside Xio's mind will not let him hear the end of it. To end that torment, and out of guilt for his actions, Xio has another of the Pantheon attempt to kill him by destroying his head completely and chaining him to a stone at the bottom of the ocean. But he survives anyway, regenerating in time, after washing ashore in southeast Asia, with no memories of his identity, but still with a screaming voice of rage inside his mind. Making his way eventually into China, he gradually recovers his memories, and after further repeated suicide attempts has to learn to live with his guilt and the furious mind of Met buried within his own. Meanwhile the entire attempt on Met's life was for naught, as thanks to their nanites, their child's body is reabsorbed back into the mother's, and the child's nanites take over that body, giving birth to a new full-grown woman. In absence of Xio and Met's leadership, the Pantheon splits into two factions, who remain at odds with each other for thousands of years. They eventually abandon the Indus River Valley and make their way to the steppe north of the Black and Caspian seas, where Keie still resides with the people she was first tasked to observe generations ago. There, they eventually meet Xio again, when he wanders west from China for the same reason. Keie, Xio, and his now-grown daughter Aten eventually heal the rift in the Pantheon, even welcoming Kron back into their ranks, and they all make their way westward into Europe (where it begins to become clear that history in this timeline has not proceeded as our history books record it), and eventually from there across the Atlantic to the New World, where in the remote Andes mountains they finally resume their project to develop space technology away from the rest of humanity, and at last succeed, despite efforts by Kron to sabotage them. For his troubles Kron is left buried in the rubble of their destroyed site as they leave the confines of Earth at last. (More details).
Centuries later and even more clearly in a different timeline than ours now, the rest of mankind are in their early space age. After a world war, the world spent a century in a cold war threatening nuclear annihilation of all civilization, polarized between, on one side, the capitalistic and nationalistic United Nations coalition of Europe, the northwestern continent called Columbia, and the southeastern continent that has reappropriated the name Auei; and on the other side, the international communist countries of Asia, Africa, and the southwestern continent called America. That cold war ended with the collapse of communism, but the following century saw in turn a "silent war" wherein the supposed victors of the cold war gradually destroyed their own values they had championed, turning on their own people and growing increasingly dependent on imperial colonization of the former communist world. Between those trends two exceptions stood, two former-communist countries that had adopted enough nationalism to survive when nationalism triumphed: China, and the Incan Empire. In these two nations grew the seeds of the next and final world war. In China, experimentation on a genetically engineered food staple unwittingly derived from the "food of the gods" that grants immortality demands the scrapping of an entire year's crop lest it lead to an unsustainable population explosion, leading instead to starvation, riots, and civil war, in which Xio secretly intervenes for the safety of humanity because China has also developed a possibly world-ending superweapon, a gravitic bomb. Meanwhile in the Incan Empire, archaologists unearthing the body of Kron accidentally set off a "zombie apocalypse" when his blood is unwittingly mixed with those of mere mortals, causing his nanites to consume their bodies from the inside out while also keeping them alive enough to spread the infection to others, which Kron witnesses and tries to fight and survive as he slowly regains his lost memories. Both of these catastrophes are ameliorated by the intervention of a new political power that the Pantheon, now called the Foundation, have engineered: from disaffected members of the Columbian and Aueian peoples, they have formed a technologically and socially advanced society distributed across both natural and artificial islands across the Pacific, including the world's first working space elevator or "Starbridge" near Christmas Island, and an economy driven entirely by friendly general artificial intelligence with fully articulated robots. This robot army puts an end to the violence in Asia and America, and rebuilds their societies into a form capable of joining the Pacific Islands International Coalition into a new, global Internation, including Starbridges of their own on Indonesia and in the Andes, on the sites where the Pantheon first attempted, and finally succeeded, in escaping from Earth. As the Internation rises in economic power, the weakening governments of Columbia and Auei eventually collapse on themselves just as the communist bloc had done centuries before, and their liberated masses eagerly join the Internation as well. Europe and its African colonies are the last to budge, but with the promise of International support, Africa stages a mostly peaceful rebellion against European colonialism, and with their dependency on Africa, Europe is soon to cave as well. The last vestiges of the United Nations survive only on the self-sufficient Lunar colonies, who continue to eye the Internation with suspicion for centuries to come. (More details).