It took some repetitive efforts. Frequent reminders. But he was receptive to the attention and truly does have exclusive access to some indispensable informants from... beyond.
"Errortale," as they call phenomena like him, could be a subtype of outcode in its own right.
There is a place like the Omega Timeline. A somewhere that's nowhere, with no features of its own but endless expanses of white except for what you bring yourself, no entrances or exits except for those who already know the way.
What sets this antivoid apart from the Omega Timeline is... the effect it has on anyone who, by some unfortunate glitch or botched cheat, gets stranded in it. Time behaves differently there, so it is difficult to say how long it takes, but staying there too long there eventually causes some kind of data corruption.
It begins with restlessness. Then, somehow, it causes the affected to develop involuntary clairaudience. (Note: It was not found that this "divination," for lack of a better term, could be attributed to hallucinations, plurality or a hivemind between others affected due to how "the voices" are capable of knowing/perceiving things the listener(s) could not, and the presentation of this condition does not align with ▢▢▢▢▢▢.)
This is, as far as we know, the point of no return before it is irreversible, as the effects begin to accelerate. The appearance of "ERROR" alerts over their bodies. Memory loss. Personality changes. Mental instability. Glitch artifacts. Colors changing and inverting. The final stage seems to be the development of completely new magic– which first presents after extreme distress and may leave a permanent pattern on their bodies– exclusive interactions with the antivoid, such as using it as displays or portals to different times and places across the multiverse, and a compulsion to return to it and resume isolation.
(Note: data corruption seems to plateau past this point. Hypothesis: failed data conversion?)
He'd been testing his abilities. He was warned it was risky. It was true, and something did happen. ▢▢▢▢▢▢▢▢▢▢
...By the time he could escape the antivoid, he barely remembered his own his name. And when he did escape, he didn't know he'd gone to not just the wrong timeline, but the wrong universe. He tried to reintegrate as if he'd gone back to his underground days of back-and-forth knock-knock jokes with her majesty Toriel. But when he discovered he'd landed in a Tale where all monsterkind were ghosts... he had a violent breakdown, and his eyesockets filled with blue strings that fell like tears and left stains on his face.
And then Spectertale was torn apart.
Perhaps it's because of this revelation's impact on him, or perhaps it's because of which Sans he used to be and what thoughts filled his skull when he was corrupted. But ever since this incident, he has been driven to do the same thing over and over again: find deviations from the Alpha Timeline and analyze the extent of these deviations before deleting them.
But it is as Core!Frisk has said: for every iteration destroyed, a duplicate iteration is also spared due to how intersecting timelines behave.
Of course, this does not stop "Error!Sans" from using his strings to puppeteer people by their SOULs, or steal people from their timelines to kill immediately, to hold hostage or to keep their SOULS as trophies. He has especially done this to Frisks to prevent them from Resetting after he wreaks havoc... just like... like...
like what almost happened in... Aftertale.
At some point. I saw this. They didn't see me but I saw that when... when Error!Sans... when he went to a common Underswap variant, he took his alternate self hostage after using the strings to pit him against his brother.
...He couldn't remember the details, but the voices did. The stolen Sans nicknamed "Blueberry" tried to appease Error!Sans, to get his guard down, learn more about him. And he did learn about Error!Sans' affection for Undernovela as if it were a TV show, about his escape from the antivoid, about Spectertale. "Blueberry" hoped to escape, yes, but he also hoped to get Error!Sans the help he needed, thus reducing the threat he would continue to pose. And Error did begin to trust the alternate from Underswap, but "Blueberry" tipped his hand and lost what little control he had over the situation. Error didn't kill him, but he left him in the antivoid. And Error came back too late.
"Blueberror" was (justifiably) angry, but would ultimately let go of Error before his outrage similarly caused permanent damage to his mental state. He would instead offer his services to the Frisk in charge of the Omega Timeline, employing his "starry" powers and even letting an uncorrupted version of himself take his place so his timeline's Papyrus wouldn't be alone. He is unstable, but he is not dangerous like Error. And especially not like Error!Undyne.
Error is not as proactive as he claims, but Error!Undyne had been looking for... me? Yes. That's right. she was looking for... me. And she and an Error!Papyrus with her who could hold SOULS hostage in bubbles... they had an uneasy agreement with Core!Frisk not to interfere with each other. But Errors can be set off by upsetting revelations, and that's all it can take to drive them to indefinite vengeance.
...There was a chance encounter between her and Error!Sans when he was wearing glasses. They couldn't have been my current frames, but... but that... that was... that was what she saw them as... and from that moment on, there would be no calming her. Blueberror was able to find and convince... Error... to face off against her, if only because he already held contempt for her. They were able to deal with Error!Undyne together, though Error!Papyrus had been lost track of, and the alliance between Error and Blueberror broke off soon afterward as... as Error... ...as 🅶🅴🅽🅾 vanished again.
...Blueberror came back to the Omega Timeline, and has been staying here ever since then.
I will have to gather my thoughts on this.
I have to... I have to... I have to...