"I see… So Mooncell was actually something created by aliens?"
Seven hours later, Shiomi returned to the chapel and saw BB there. Naturally, he brought up the topic of Mooncell again.
Although BB had explained it before, now that Shiomi was alone, she offered a more detailed explanation.
"That's right. Mooncell was originally a construct left on the moon by ancient aliens to record information about Earth. It doesn't have artificial intelligence because it concluded that, as a recording medium, it didn't need one. Instead, superior AIs like me were created as terminals to observe humanity more efficiently."
"Then the Holy Grail War on the moon…" Shiomi continued.
"The moon's interior, which is structured by Mooncell, is itself a boundless Holy Grail."
"So the moon itself is the Grail?" Shiomi instinctively looked up at the ceiling. "The thing Fuyuki's magi spent their entire lives chasing… it's just sitting up there…"
"That may be true," BB said, "but Mooncell has determined that the time hasn't yet come to open itself to Earth. So even the King of Magecraft can't make direct contact with the Mooncell. The Holy Grail War on the moon is a system it uses to select its own user. Of course, that system hasn't been activated in this world yet."
"If it's not open to humans, then why choose me? Why send you to reveal its existence?" Shiomi asked.
BB hesitated, unusually at a loss. "I'm sorry, that part is classified. Mooncell hasn't granted me access to that information."
"How mechanical… Well, it is a machine," Shiomi muttered, then asked, "If I win, Mooncell's Holy Grail should be far more powerful than the Fuyuki system, right?"
"Of course. Unlike the Fuyuki system—constructed by human magi under the observation of the Second Magic and based on the Third Magic—Mooncell's Holy Grail draws its power from its own astronomical computational capacity. The winner of the Holy Grail War only gains the right to use it. Whether altering the past or predicting the future, the user can reshape the world as they desire," BB replied.
Shiomi blinked. "Altering the past… wouldn't that create a Singularity?"
"Of course not. Mooncell calculates outcomes that can continue to develop without being pruned," BB said matter-of-factly.
"That's seriously impressive…" Shiomi crossed his arms.
"The original BB was also a superior AI, created with a soul to manage the Holy Grail War," BB added. "But I'm a bit different—I exist to guide Dad along his path."
"The original?"
"Don't worry about it. Just a record that's fallen into an imaginary number event," BB said. "But Dad has already met the people involved in that incident."
Shiomi froze for a moment, then quickly pieced it together from among the people he knew.
"…Hakuno Kishinami and Gilgamesh?"
"Yeah. Their appearance in Fuyuki and later in Uruk was arranged by Mooncell," BB said. "But letting outsiders interfere too much with this world isn't ideal. That's why they can only show up in crises on the scale of the Incineration of Humanity."
"Then Fuyuki—"
"Of course, Mooncell foresaw the King of Magecraft's potential wish, so it handed the Holy Grail over to you all to interfere. Still, since Gilgamesh was just a contractor, he chose to side with the King of Magecraft." BB puffed up angrily, clearly displeased. "BB's so mad she wants to step in herself, but Mooncell won't let her!"
"Ahahaha…" Shiomi could only let out an awkward laugh.
Given Romani's situation now, and since things hadn't ended in disaster, he didn't feel like nitpicking over the past anymore.
"So, Passionlip—" Shiomi turned to the girl standing beside him.
Because she was aware of her unique weight, she didn't sit on the bench but used her massive claws to support herself in a seated position.
"J-Just call me Lip," she said nervously. "D-Dad…"
"You don't have to force yourself to call me that. BB only does it because of her weird sense of humor," Shiomi said with a sigh.
BB immediately objected. "I'm being totally serious!"
"Who knows," Shiomi shrugged with a teasing grin. "So Lip, you're actually different from BB—you weren't sent here by Mooncell?"
"Yeah… I thought I had disappeared. But now, I've come back like this…" Lip glanced at BB. "Melt must be the same."
"But this version of Mooncell seems to have noticed some growth in your mental states and decided to reassess your value," BB said proudly, giving Lip's cheek a playful pinch. "That's why I was sent to retrieve you both."
"I see…" Lip's expression grew a little complicated.
She looked both happy and lost, unsure of what to do next.
Seeing that, Shiomi gently said, "Lip, maybe you were originally created as a weapon, meant only to fight. But… you've already developed a soul of your own. And whether you're an organic lifeform or an informational one, a soul's value doesn't come from what you're made of."
"Really?" Lip's eyes sparkled with curiosity.
She didn't understand humans or their emotions, so Shiomi's words meant everything to her.
"It's your future choices and actions—and your willingness to take responsibility for them—that define the value of your soul," Shiomi said seriously. "Whether you want to have a noble soul or a lowly one, that's entirely up to you."
"But isn't that just how humans live?" BB said in a slightly correcting tone.
"At this point, there's no real difference between humans and superior AIs—only a difference in capabilities," Shiomi replied calmly. "At least, that's how I see it. You're free to laugh at my naïve view."
"Sigh…" BB didn't laugh. Instead, she pressed her lips together and let out a soft, understanding sigh.
Passionlip followed with a smile.
And finally, even Shiomi couldn't help but smile too.
Just then, Artoria pushed open the small door from the inner room to the chapel.
"I was wondering why it was so lively in here. So it's the Master chatting with you two." Her usual gentle smile was as radiant as moonlight.
"Feeling rested?" Shiomi asked with concern.
"Very much so. I rested so well, in fact, that they sent me out to check on Master."
Artoria nodded and added with a teasing smile.