Later, in the Sky Room on the eighth floor where the Chaldea team was staying.
Aoko Aozaki, who had abruptly appeared in front of her own corpse, was brought here for questioning.
Besides Shiomi, who appeared suspicious, and Tobimaru Tsukiji, the detective in charge of investigating and gathering evidence, Touko Aozaki and Alice Kuonji were also present.
The others, though still under suspicion, were temporarily dismissed to move about freely.
After all, even if Aoko, as the victim, had appeared alongside her own corpse, the fact remained that a murder had unquestionably taken place.
In terms of both motive and capability, Shiomi and Touko Aozaki, who both knew Aoko Aozaki, could not be ruled out.
Morgan, meanwhile, put on an expression that clearly said, "My husband has worked hard to clear his suspicions, so I'll go rest," and left with Scáthach and the others to enjoy tea and sweets.
"So then, would you mind explaining what's going on, Aoko Aozaki?" Shiomi raised an eyebrow. "Touko told me that the Fifth Magic has the power to borrow from the universe. For example, it can throw five minutes of one's own death, or someone else's, into the distant future, erasing the possibility of that death. Or by paying with one's own time or another's, it can make a future version of oneself—already complete—manifest in the present."
"But all of that comes at a cost. The universe's energy is finite. It can't be consumed endlessly."
"Phenomenon Judgment is the clearest example of that."
"As a Magician who inherited the Fifth Magic, Aoko Aozaki can draw energy from the universe to use it. In exchange, the universe immediately incurs an energy deficit. To prevent that deficit from causing problems, she casts the deficit itself into an even more distant future—perhaps a universe that exists after humanity and the world have already been destroyed."
"Still, in Touko's view, the outcome that includes time travel is only a byproduct of the Fifth Magic."
"After all, the management of time travel and parallel worlds already falls under the Second Magic."
"The same magic isn't categorized twice."
"Oh… that's surprising. Big Sis really told you all of that?" Aoko looked at Touko with an easygoing expression, tinged with a bit of distrust. "That saves me the trouble of explaining too much. But honestly, I don't think Big Sis killed the 'first Aoko.'"
"You're not suspicious of me at all?" Touko said, amused.
"If you really wanted to kill me and actually succeeded, the scene would have been clean. There wouldn't be a single drop of blood left," Aoko replied casually. "Though that so-called Death Rune does bother me…"
Alice spoke up at that point. "I examined the body. What was used to kill the 'first Aoko' wasn't an ordinary Rune, but Primordial Runes that disappeared back in the Age of Gods. The Runes Miss Touko possesses aren't of that kind."
She was referring to the Rune Stone Touko had created by replicating Primordial Runes during their battle in the old school building. Its power was completely different from what had killed Aoko.
"Hard to say." Touko adjusted her glasses, her gaze drifting toward Shiomi.
If she had known Shiomi could so readily provide the thaumaturgical foundation for Primordial Runes, she would have prepared far more thoroughly before returning to Misaki.
"Never mind. We can deal with that later." Aoko blinked, then grew serious again as she returned to the original point. "Like Alice said, the dead me can be conveniently called the 'first Aoko.' The current me is the 'second Aoko.' Both are me. I jumped here from… a very distant future."
"Just how distant are we talking?" Shiomi asked.
"I can't answer that. As a Magician, I'm forbidden from disclosing anything about magic to the outside world—its details, principles, or even my own impressions." Aoko refused outright.
"Oh, I see." Shiomi didn't bother pressing her about exactly which point in time she came from.
"The reason I jumped is because a Singularity appeared at this time and place," Aoko said bluntly.
On the way upstairs, Touko had already explained why the Chaldea team was here, so there was no need to go over it again.
However, this Aoko and the deceased Aoko came from different timelines.
Conversely, any information the previous Aoko had obtained here was completely unknown to this one.
"So why did you come to this Singularity, Magician?" Shiomi continued.
"It really feels like I'm being interrogated…" Aoko's face darkened with irritation for a moment before returning to normal. "Honestly, I detected the Singularity and figured it might have something to do with me, so I jumped here from the future to 2001."
"But you did die," Shiomi pointed out. "Even if a future version of you from a different point in time came here to resolve the Singularity, once it's over and the Human Order Foundation Value begins its calculations, wouldn't your death become a fixed outcome?"
"Your reasoning is spot-on. Looks like you know quite a bit about the finer details of the Human Order," Aoko said. "But as long as the Singularity hasn't disappeared, the death that happened here won't affect my future self for now. It was precisely because my future self lost information about what happened to me here that she sent the 'second Aoko'—me—to this place."
As she said that, she broke into a confident smile with a hint of foolishness to it. "As for my death here, just think of it as a temporary debt. Once the Singularity is resolved, that debt will be erased. No need to worry about the Human Order Foundation Value at all."
"Magicians really are convenient," Shiomi let out a quiet chuckle. "I wish the humans who died in Singularities could be preserved like that too. Anyway, I think I get it now. Your method is basically like that Stand called D4C from JoJo. Except that one pulls in versions of itself from parallel worlds, while you're slicing vertically through different timelines to grab yourself from a specific moment. Either way, you can keep sending them in, one after another, endlessly rushing to the Singularity."
"No, no, that's not right. A rocket pencil is a much better analogy. At the very least, this is more like a vertical version of Zelretch's magic," Touko suddenly objected, her glasses flashing with a strange gleam.
"What are you talking about? Back when we were young in the eighties and nineties, JoJo was already super famous," Shiomi shot back.
Aoko looked exhausted. "…As much as I hate to admit it, I think Big Sis's analogy fits better…"
Alice wore a completely speechless expression and chose not to comment on their disagreement.
Tobimaru Tsukiji, the only non-Mystery ordinary person in the room and also a detective, looked utterly lost. Even so, it was clear he was trying his best to follow along.
"Tch…" Shiomi clicked his tongue in defeat, then raised his eyes. "More importantly, don't you think someone's missing? I noticed it back in the lobby."
"You mean—" Touko paused, thinking.
"Shizuki-kun?" Alice looked toward Kesshi. "I haven't seen him today either. Do you know where he went?"