Rozen then told the three sisters about his conversation with Shouko, letting them know the truth.
Upon learning that they had the potential to become Machine Dolls—at the cost of Rozen's vitality—the sisters were both stunned and horrified.
Rozen quickly reassured them.
"My vitality is more than sufficient. No matter how much you absorb, it won't affect me in the slightest."
His explanation eased their worries.
"So... Onee-sama and I will eventually become Machine Dolls?" Komurasaki murmured, her voice a mix of disbelief and wonder.
"Phase Transition..." Irori whispered to herself.
The three sisters had been completely unaware of the Phase Transition until now—the very principle and purpose behind their creation.
None of them had ever imagined that they were all candidates to become Machine Dolls, destined to reach that pinnacle one day.
Even now, they seemed unable to fully process it, their expressions still dazed.
Yaya, however, was the first to react with anger.
"Shouko only gave Yaya to Rozen so Yaya could steal his life?! That's unforgivable!"
She clearly couldn't accept this part of the truth.
"But this was my choice too. You don't need to blame Shouko," Rozen said gently. "If it were any other puppet craftsman, they wouldn't hesitate to sacrifice thousands of lives just to create a Machine Doll."
Still, this wasn't the main point.
The real focus was Rozen's next decision.
Now, there was no reason left for him to stay in this world.
The massacre of the Akabane clan had been resolved.
His family had been revived and would eventually rise to the pinnacle of the nation with the support of the Izanagi.
The Machine Doll had already been born and left for another world, disappearing from the Night Party.
Even Shouko's original purpose for having Rozen participate in the Night Party had come to nothing, with no need to continue.
Therefore, Rozen decided it was time to move on—to the last world where he still had regrets, to settle everything left unresolved there.
Once that was done, he would have no lingering regrets. He could return to Chaldea, resolve the final Singularity, restore Human Order, save human history, and erase all calamities.
This was what remained for him—the last few steps of his journey.
So, Rozen felt it was time to leave this world and move on to the next.
As for the Night Party, he would simply forfeit, leaving the title of Wiseman to Charl—or perhaps Loki.
They needed it far more than he did.
Rozen had no attachment to the position and could easily withdraw, taking the Setsugetsuka sisters with him.
However, this time, he wouldn't be bringing them along.
Irori, Yaya, and Komurasaki would stay behind.
The reason was simple.
"Shouko plans to leave her homeland and travel the world alone, but you all know how dangerous that would be for her."
As the foremost expert in crafting Automaton Dolls, once Shouko cut ties with her country, she wouldn't just face pursuit and assassination attempts—other nations would covet her techniques, even her very person.
Despite knowing this, Shouko had still chosen to leave.
So, Rozen wanted to do something about it.
Namely—
"I want you three to stay by Shouko's side, protect her, and make sure she doesn't come to harm."
That was his decision.
"But what about you, Rozen?" Yaya immediately pressed.
"Me?" Rozen smiled. "I'll go finish what I still need to do."
In other words, he would be parting ways with them.
"W-Wait—"
"Rozen—"
Irori and Komurasaki tried to protest.
It was clear neither of them wanted to leave Rozen's side.
Even Yaya frantically objected.
"No! Yaya is Rozen's Automaton! Yaya must stay with Rozen!"
She declared this loudly.
"Then are you saying Shouko's safety doesn't matter?" Rozen countered.
"Onee-sama and Komurasaki can stay with Shouko!" Yaya argued without hesitation. "Rozen only needs Yaya! In fact, this is the perfect opportunity!"
She accidentally let her true feelings slip.
"Yaya! How selfish!"
"Trying to hog Rozen all to yourself? I can't believe you, Yaya-onee-san!"
Irori and Komurasaki immediately protested.
But Yaya only grew more defiant.
"Rozen only ever needed Yaya in the first place! Onee-sama and Komurasaki were never necessary!" She threw her hands up dramatically. "Ever since you two came, Yaya's role has been shrinking! Onee-sama handles all the housework, and Komurasaki keeps stealing Rozen's lap and hugs! Yaya can't even drug anyone or sneak into his bed anymore! Don't you think that's going too far?!"
Before Irori or Komurasaki could respond, Rozen sighed.
"No, no matter how you spin it, you're the one who's going too far here."
Drugging? Really?
Knowing Yaya, she probably was serious.
This only reinforced Rozen's decision to leave her behind.
"Yaya, you're the most suited to guarding someone important. Shouko's safety depends on you." He placed a hand on her shoulder. "And don't worry about me. I'll form a new contract with all of you—one that lets us communicate mentally and even summon you to my side if needed. So, just obey me this once, alright?"
Though he was leaving, he intended to form Absolute Contracts with Irori, Yaya, and Komurasaki.
Only then could he depart with peace of mind.
"But—"
Yaya still wanted to argue.
"No buts." Rozen cut her off. "Listen to me, Yaya. One day, I'll come back for you."
At that, Yaya finally fell silent.
Reluctantly, she nodded.
Seeing even Yaya relent, Irori and Komurasaki had no choice but to reluctantly agree as well.
And so, everything was decided.