"A worldline is a conceptual theory proposed by Einstein. She collectively referred to time and space as four-dimensional spacetime, and the trajectory of a particle moving through four-dimensional spacetime is called a worldline.
Although this is merely humanity's one-sided understanding of regions it cannot observe, it has at least allowed humanity to glimpse part of the world's true form.
Being able to glimpse it does not mean humanity can understand or come into contact with it. Just like trying to scoop the moon out of the water, humanity's incorrect understanding can instead guide it toward the exact opposite of the truth."
"So, Id, you don't need to pessimistically worry about the worldline destroyed by the Herrscher of Death. A worldline isn't truly a world in the literal sense. It's merely a collection of various possibilities of time and space. Otto's claims were entirely alarmist."
"Think about it. Why did Otto want to restart the world?"
Id: "To revive Kallen."
"Exactly. He wanted to revive Kallen in the truest sense. Otto partially concealed this from Durandal—or rather, at the final moment, Otto did not emphasize this point to Durandal again. That was why she failed to understand the true meaning behind it."
"Look. Even though the worldline changed, the people we know haven't actually changed. They're still truly themselves. Everyone we know is still alive and well, aren't they? Maybe a few more even came back to life somewhere we can't see. Death and new life always go hand in hand."
Mm. Lifting the coffin lid on the spot.
Id tilted her head, still finding Conductor's explanation somewhat strange. "Is that really how it works? It still feels kind of weird."
Seeing Id remain so stubbornly unconvinced, Conductor couldn't help showing a somewhat helpless expression. She had already explained it in such detail, yet it seemed Id had still been led astray by the original main storyline of Honkai Impact 3rd.
After all, the original protagonists' opposition to that plan had been extremely firm, while Otto's ostensible plan had been layered beneath lie after lie by that selfish fool.
"You simply haven't accepted certain things that violate the rules of the world yet, which is why you feel the need to discuss whether the result is good or evil from a philosophical perspective. But when facing a Herrscher capable of tampering with the rules themselves, the first thing we have to do is break free from our own fixed common sense."
"The world is constantly changing, so couldn't we also interpret that as the previous world being erased and the one we're in now being a new world? No one can step into the same river twice. The principle is the same as reconstructing a worldline."
"We can't exactly declare that the world is being destroyed every second, can we? Mm, although that interpretation isn't exactly wrong either. Perhaps that's precisely why the authority over destruction and rebirth can act upon worldlines in the first place."
"In fact, merely existing on the original worldline already means we aren't free. We can only passively accept the present and passively move forward along the worldline."
"Restarting the worldline means we can break free from our passive relationship with the 'present.' If we still cling to preserving the 'old world' at that point, we'd instead be restricting the openness of our own future."
"Of course, I'm not saying we absolutely have to leave the 'present.' I'm only saying that changing the 'present' is also a choice. It's just that the Herrscher of Death's authority forcibly dragged us onto the current worldline. In a certain sense, you could also call it an extension of the original worldline."
"But compared to Otto's method of directly tampering with five hundred years of history, which could potentially affect whether later generations were even born, the worldline altered by the Herrscher of Death clearly can't reach anywhere near that far—even though she has already approached False God Otto's level, the upper limit of Imaginary energy within her Herrscher Core still restricts what she can accomplish. The Herrscher of Death isn't Finality, after all."
Id nodded, tentatively accepting the explanation. Seele hadn't actually killed anyone. That was a good thing.
Otherwise, once Seele returned to normal, who knew how deeply that gentle girl would blame herself?
"But why can Seele do something like that? No matter how I think about it, authority capable of manipulating the Imaginary Tree is way too far beyond the norm."
"Don't forget. Honkai itself parasitizes the Imaginary Tree and uses it to manipulate real space. As the Herrscher of Death, a messenger of Honkai manifested in reality, when she reaches that critical threshold, she indeed may be able to mobilize the potential energy hidden between reality and the Imaginary."
"All right. Now that you understand what happens after a worldline changes, let's move on to the second question."
"Unfortunately, using the authority over life and death to reconstruct a worldline is an extremely thorough, top-level reconstruction. In Otto's words, it leaves no trace. In other words, we couldn't possibly—and shouldn't—retain memories from the original worldline. Such a thing simply shouldn't exist."
'Grafting worldlines' is only a general way of describing it. In reality, worldlines are clearly separated from one another, and between worlds lies an unknown expanse of void that is nearly impossible to cross. Even grafted worldlines cannot establish contact through ordinary means in reality."
Since there were ordinary means in reality, naturally there were also extraordinary means. To cross that domain, Vill-V could still think of only one method.
Id knew that method perfectly well too, because she had personally experienced it twice already.
It was also the only method that imitated the birth of the universe—creating an Imaginary singularity and releasing zero-point vacuum energy.
And then, start the train! Choo choo choo choo—
In other words, exactly what Vill-V had once done to herself and Planck in the Sea of Quanta.
Although it appeared to be nothing more than an operation performed in reality, its true essence was to use the Second Divine Key, Cosmic Juggernaut, as an anchor and solidify the Imaginary by relying on reality.
As for the complicated principles involved, only Expert and Scholar could explain them. But Expert wasn't here right now, while Scholar... would only make the explanation even harder to understand.
It could be said that without preparations made in advance, accomplishing such a miracle was fundamentally impossible.
Unless Pardo came knocking on the door!
Id: "But we haven't done anything like that this time. There's no reason we'd somehow be spared when the worldline restarted... Don't tell me Magician secretly made preparations."
Magician, automatically taking the blame.
Magician stroked the crying-cat head and said, "Waking up every morning to discover the worldline had changed... I'd love to do that, but Conductor never gives me the chance... I did prepare a quantum-entanglement magic trick, unfortunately, we're special. There aren't any other Vill-Vs out there resonating with us."
"I feel like you just casually said something incredibly serious, Magician."
Id frowned and scratched her head, realizing the situation wasn't simple.
Conductor snorted unhappily. "It is serious. Id, let me explain. If you want to possess memories from other worlds, there is one method—still using the Second Divine Key to establish quantum entanglement with Vill-Vs from other worlds."