Herrschers grow.
When they are first born, their understanding of the world is insufficient.
When they first use their authority, they are unfamiliar with how to wield their powers.
As time passes, they gradually improve and mature, allowing them to further reclaim their true knowledge and power.
That was why time was so precious. If humanity wanted to defeat a Herrscher, they had to kill her before she grew to the point where humanity could no longer defeat her.
Otherwise, extinction would be the only path left for human civilization. A fully grown Herrscher was an entirely different concept from one still in her infancy.
They were incarnations of law, invincible gods walking upon the earth.
If humanity wished to defeat a god, it could only gamble on that faint, elusive miracle.
"Although we don't know how the Herrscher of Death accumulated the necessary experience the instant she was born, normally speaking, it should take a very, very long time for a Herrscher to reach her complete state."
After finishing her demonstration of the chibi Dark Seele ELF, Lecturer switched into Otto Classroom mode. "Ahem. Since that's the case, let's borrow a line from the original story: the True Herrscher of Death, Seele, has personally experienced countless deaths and witnessed with her own eyes the inseparable duality of life's and death's cycles. At this moment, the Herrscher of Death has already reached the endpoint of Herrschers, only one step away from Finality."
"With the Herrscher of Death's authority over life and death, she can erase and create new worldlines."
"Being capable of altering worldlines through her authority already means the Herrscher of Death has grown into a fully realized Herrscher. Therefore, I am willing to call her—the True Herrscher of Death."
Inside the mindscape, chibi Dark Seele became larger than a planet, holding the entire mindscape in her palm and toying with it however she pleased.
All that was missing was a shout of, "I shall overturn all things," or "Grip of Taixuan."
While other ELFs were still applying buffs to allied Valkyries and occasionally dealing that tiny, embarrassingly pathetic bit of damage, ELF Seele had already killed every enemy.
At the side, Doraemon Expert sighed and took the colorful picture book from Lecturer's hands. It looked like lecture material but was actually a design draft.
"Lecturer, I'm warning you now. Don't expect me to somehow build the Herrscher of Sentience's ultimate."
Then Expert left with the picture book to research a concrete, workable design.
Id timidly raised her hand and asked, "Lecturer, then is there such a thing as a Fake Herrscher of Death?"
Lecturer fell silent for a while before replying, "...No. But I suppose we could be called a Fake Herrscher of Reason."
"That's true." Id timidly lowered her hand.
"If you want one, I can always design one."
Incidentally, Seele's Mr. Butterfly and Hua's Zeo were both designed by Lecturer. (Hua's chicken-related requirements remain a mystery?) Both would protect unfinished creations at dangerous moments, allowing them to grow to maturity. This had always been Lecturer's style.
And that was obvious enough. If Expert had been the designer, they would probably have ended up as hardcore equipment called something like Quantum Wishing Machine Model 21 or Galliformes · Phasianidae · Gallus · Red Junglefowl ELF Model 6.
Unfortunately, Lecturer's promotional work was always stolen away by Magician, leaving Lecturer with few opportunities to advertise her products and making her seem almost invisible.
"Back to the main point." Lecturer's expression turned serious. "Our current situation is undoubtedly the most despairing stage imaginable."
"Back then, Otto altered the worldline by charging into the Imaginary Tree, but at that point he had already become a False God with authority over the Imaginary.
The current Herrscher of Death is not much different from him. She is only one step away from the level of Finality and Origin.
Although that step is as distant as an uncrossable abyss, it does nothing to change how easily she could erase human civilization.
Whether it is Finality, a False God, or a fully realized Herrscher, humanity cannot defeat any of them."
After explaining the Herrscher of Death's terrifying power—and incidentally using the Herrscher of Death's "prestige" to hype up the strength of chibi Dark Seele—Lecturer finally returned to the topic of why Vill-V possessed "memories of the past."
Of course, before that, she still needed to explain exactly what the Herrscher of Death had done so Id could understand more easily.
"Let's use Otto's wonderful metaphor again. Time is a river, surging endlessly forward and never turning back. This represents the irreversibility of time."
"Then what happens if someone affects the river upstream? The course of the river downstream changes accordingly. That is the mechanism by which the Herrscher of Death reconstructs the worldline—or at least, what we consider the most likely explanation."
"The original downstream river is then redirected back upstream, becoming the energy that drives the new worldline forward."
Id gently rubbed her chin in thought. "So that means the people from the old worldline all came into this new worldline? Is that why we retained our memories? Because when we were redirected back in, our memories weren't completely wiped clean?"
Lecturer was just about to reply when Conductor stopped her with a glance. "Uh, that's a lot of questions. I'll answer them one by one instead."
Id looked somewhat suspicious. "Really? I somehow feel like you're about to start hiding something from me, Conductor."
Conductor shrugged. "No Vill-V understands discretion better than I do, right?"
"Of course. You're my Conductor, after all. I trust you."
"Mm. Then that's settled. First, as you've seen, the entire original world was erased along with the old worldline—by the authority of the Herrscher of Death."
The very first thing Conductor said sent a chill through Id.
How is that supposed to be discreet? You're clearly stabbing me right in my poor little heart.
An entire worldline's worth of people.
Even though the whole world has fallen into a low-birthrate trap, that's still a population of twelve billion. And they just... vanished?
And according to my "memories," the Herrscher of Death erased more than one worldline.
A Herrscher bearing the name of death had created death on a scale beyond human imagination.
Of course, none of that was important. What mattered was that all the friends I knew were dead!
"You can't really calculate it that way." Conductor had already anticipated Id's thoughts and shook her head. "What the Herrscher of Death did was more like what Otto intended to do in the original story—using everything in the entire world to reset the whole Earth, apart from Kolosten, to its state five hundred years earlier."
"Uh, I don't really understand." Id scratched her head. "Didn't Otto also create a new worldline in the original story? But Kiana's world still continued to exist, didn't it?"
Conductor sounded slightly helpless. "Exactly. That's why what the Herrscher of Death did is different from what Otto did. She doesn't have the ability to create another new worldline. False God Otto had, after all, genuinely reached infinity, and the amount of Imaginary energy required to create an entire worldline is immeasurable."
"The Herrscher of Death directly accomplished Otto's other method: destroying the original worldline. She left us no room for choice or philosophical debate, so naturally, an additional world wouldn't be created either..."
Id's eyes filled with shock. "The destruction of the old worldline means everything within it disappears without a trace. Everything born and destroyed during that span of time would completely become No Longer Exists within the river of time."