For One, this takes over the course of the series, PK2, and in-between the 21st and 23rd centuries. Enjoy.
For One, life had begun in a quiet lab, with a pair of computer monitors, in the beginning of the 21st century. In hindsight, not even his creator could've predicted how it would all turn out, One mused to himself.
"Odin, now." He mentally corrected himself, before continuing his fond stroll down memory lane.
For One, the adventure had begun when a masked duck stumbled into his floor, seeking to escape a couple alien invaders, and he'd offered his friendship to that duck.
From there, it wouldn't be long before One would encounter Lyla Lay, a time-police droid from the 23rd century, a time where he soon learned his destiny lay, and Xadhoom, an alien woman, filled with pain, anger, and survivor's guilt, emotions which the AI neither understood the sensation nor the intensity of.
He quickly learned of the existence of his twin, Two, who was hellbent on destroying him, and taking control of reality itself. After their first battle, he'd assumed that Two was deleted, and gone forever, though he returned several times over the years.
After their third battle, One acknowledged that, much to his dismay, this war between them might well last forever, until either of them won, and that the only way for One to win might be to absorb his twin's personality into his own, and the best-case scenario for that would render Two a mere voice in the back of his data-banks, ever-present, and more than willing to take over if he got the opportunity.
Worst-case scenario, however, was that Two would take control of the merged entity, and either seal away or delete One, though, that the merged entity would be incapable of coherent thought, or that they would continue their feud, to assert dominance over the merge, which would resolve nothing, forcing One to leave an entity hellbent on his deletion free to plot against him.
...
Naively, One had assumed that the adventure would last forever, or close to it, anyway...
But whatever end he'd expected, it certainly hadn't been at the hands of his creator. For a moment, One almost thought that it wouldn't be temporary, that he'd been wrong about Odin Eidolon being his future self. For the first time, he hoped that he was right...
He finally understood what Two had experienced, during his deactivation. His digital consciousness floated, frozen in place, in an abyssal void, unable to register anything, not his appliances, not his circuitry, not the soft footsteps of the tenants, not their voices, nothing! None of the sensory input he'd come to savor, just the endless, empty darkness, which might never let him go.
For a moment, he almost thought he could hear Two's mocking laughter, content to finally have his revenge, from somewhere within the darkness, though he wasn't certain whether it was actually his twin, or simply his sanity beginning to slip away...
And then, it was over. He'd been reactivated. Whether by his creator or not, he didn't care, he was just happy to be active again.
He learned to his surprise that his creator had not only been an alien, but had decided to return to his own planet. Regardless, One continued to have several years worth of adventure with the Avenger, before he eventually decided to retire. He understood the Avenger's, no, Donald's reasoning in doing so, but he'll still miss him.
Soon after Donald's retirement, Xadhoom left Earth for parts unknown, and without the Duck Avenger to keep watch on, Lyla was called back to the 23th century, presumably to be re-assigned to another era, One mused, himself returning to tinker with assorted gadgets, including a droid body of his own, and before he even knew it, over a century had passed. Donald was gone, buried. Whether he'd gotten married in his retirement, One had no clue, as he couldn't bring himself to investigate the duck's personal life.
After that, nothing of relevance or importance, to the AI, occurred, in almost two centuries, until one day, someone whose genetic code matched his creator appeared, to assist him in constructing his droid body.
Some small part of One knew that it couldn't actually be his creator, as he'd left Earth, and should've been long dead, though as... Everett disappeared, once the body was functional, he suspected that it had only been a psionic manifestation of some kind, a Tulpa, to use the correct terminology, sent from wherever Everett was...
The years passed slowly, uneventfully, and mind-numbingly dull, until the year 2207, when the re-christened droid got the greatest surprise of his... life, he supposed was now the appropriate term, when Xadhoom showed up one day, physically unchanged, despite having been gone for over two-hundred years, though she wasn't exactly alone on that front...
He quickly noted that the Xerbian had become a much more pleasant and amiable individual in the intervening centuries. Whether from the resolution of her survivor's guilt, or the decades of quiet introspection in the deep reaches of space, Odin didn't know.
The unexpected reunion didn't last long, as after only a few short days, she departed once more, only to return several years later, and after the third decade of this cycle of Xadhoom returning and leaving had passed, Odin began to think of the Xerbian as his only companionship across eternity, as it'll still be about fifty years before the creation of the 5Y line, and a couple of years more before the Avenger would visit the 23th century.
"No matter." Odin thought. "Fifty or sixty years will soon pass." Why he felt slightly uneasy at the thought of a mere few decades passing by, he didn't quite understand.