Multiverse Cross Ex

"Mitsuya. Tell me, just what on earth have you done?"

Inside Reiri's office—which, by the way, doubled as the principal's office—Mitsuya stood before her, his expression unreadable.

However, he wasn't alone.

Another woman stood beside Reiri, watching the exchange in silence.

Mitsuya knew who she was.

After all, based on his understanding of this world, her identity was no secret to him.

Still—he turned his attention back to Reiri.

"…Whatever do you mean by that?"

BANG!

Reiri slammed her fist against the desk, her frown deepening.

"Don't joke with me. I've already heard everything from Aine herself."

'Tsk.'

Mitsuya clicked his tongue.

His gaze darted around the room briefly as he considered his next words.

A few moments passed—then his eyes settled on Kei, who stood beside Reiri, tablet in hand.

"…Ms. As a scientist, surely you're familiar with superluminal particles."

Kei blinked, momentarily caught off guard.

However, she quickly recomposed herself.

Her fingers danced over her tablet's screen, and within moments, a holographic panel flickered into view in front of Mitsuya.

[Are you referring to tachyon particles? Hypothetical particles that always travel faster than light? What about them?]

"Hypothetical, huh?"

Mitsuya relaxed his shoulders slightly, crossing his arms as he then continued.

"Then what about magic? And where does the energy used to operate the Hybrid Gears come from?"

[Huh?]

Kei blinked, momentarily stunned by the question.

Yes—if the Hybrid Gear's energy recharged itself, then it clearly wasn't based on conventional electricity.

Nor did it deal with solar energy that regained it's energy from the sun.

Yet, it still needed to resource itself.

And that… That fundamentally violated the law of conversation of energy that energy can neither be created nor destroyed.

The energy lost in a sense is used up, or in better terms destroyed.

"After all… the Cores recharge on their own, don't they? Then, what exactly are tachyon particles?"

Since they theoretically move faster than light, then, in this case, energy can be recreated as it's destroyed.

And. Kei's mouth hung slightly open. For the first time—

She wanted to argue against another's reasoning. His reasoning.

But as characteristically of her, she didn't.

Instead—she fell silent, her mind already running through what he'd just said.

If the Cores didn't rely on luminal particles, then perhaps, was a degraded form of superluminal energy was being harnessed instead.

Superluminal particles—moving faster than light—couldn't be captured under normal circumstances.

But yes, a degraded form that didn't move faster than light would take time to repair.

A scientist had once argued that it was because of the difference in their worlds, assuming that that world was rampant of it.

Then, if that were the case, wouldn't that mean the energy getting restored used some sort of particles in substitution instead?

[Yes. Like Master theorized, the concept of recycling surrounding particles to generate energy from seemingly nothing can be actualized. There exist enough foreign particles in the air to make this possible.]

It was Navi who delivered this news, and Mitsuya nodded as he listened.

No matter how you look at it. Causally opening a space-time portal at several intervals would influence this world in either a good or bad way.

Reiri, however, scowled.

"…I'm not following what you two are talking about," she admitted. "And how does this relate to Aine's Hybrid Count suddenly being at full power?"

That was supposed to be something exclusive to the research being conducted on Eros.

However, though she couldn't understand it fully. With Kei's expression, she was sure his words held credit behind them.

"Let me ask you this then, Commander—how do you recharge your terminal?"

"Hah?"

"By connecting it to a power source, no?"

A tick mark twitched on Reiri's forehead. Since when did this brat start lecturing her?

However, glancing over at Kei, who was listening intently—as if her entire world view had just opened up—Reiri chose to hold back.

"…Hybrid Gears don't work like that, they don't have any direct power source that can recharge them. Even if such a system existed, the Gear that could theoretically recharge another Gear would be nothing more than a glorified power bank—ultimately useless in any other thing than that."

At this point, Reiri clenched her fist.

There was no way she could have known Mitsuya was hiding something.

But his words, they were pointing at something, something she knew well.

But in this case, it wasn't something, rather, someone. Still—Reiri wasn't foolish enough to cut him off.

For a kid like this to know more than she originally gave him credit for. Now she was starting to get interested.

And, now that she thought about it… It was no wonder her mother had deemed "him" useless.

Because, just like Mitsuya said—

A Hybrid Gear built purely as a power bank would serve no real function in battle.

Sure, it could still fight, but its combat capabilities would be lacking on multiple levels.

"However," Mitsuya continued, "what if you could recharge that terminal you use—through other means?"

"Solar. Wireless. Or something else entirely—if, of course, it had that function."

"…And yet—" He leaned forward slightly to her desk with a smile on his face. "What if that function wasn't limited in option—but something universally available?"

That Sealed It.

While she was still somewhat lost, one thing was clear—

It was possible to recharge Hybrid Gears through alternative means.

This wasn't just good news.

This was GROUNDBREAKING.

Yet, she wasn't one to jump to conclusions.

[Is Mitsuya-san trying to say that he can manipulate superluminal particles using his powers?]

Mitsuya-san?

Reiri momentarily paused.

Why was Kei, who was older than Mitsuya, suddenly addressing him so formally?

…But that didn't matter.

Mitsuya let out a short laugh.

"Hahaha. I'm not a god, but yes—it's possible."

"Though, not in the way you might be thinking. Even with my «Territory» at full capacity, directly capturing particles moving at light speed would be impossible for me to process."

He leaned back, from the table, crossing his arms.

"However—in a way—I can tamper with some particles of the same source. Bad news, though—it takes too much of a toll on my body. So I'm sorry to disappoint you in that regard."

He said it so matter-of-factly.

And though he did, Kei couldn't help but cover her mouth while Reiri, on the other hand smiled.

This is good.

Though it may be selfish of her, with him, she could keep her brother away completely from this mess.

Of course, it was surprising, and in the past few days, he'd been surprising them.

Yet, that brings her to this question.

"Mitsuya, please, the truth: are you the pilot of that machine?"

Reiri, after no thought apparently, asked this. There was no reason to wait anymore.

He'd told them all this after all, and there wasn't a need to remain curious.

"Doesn't the commander know the answer already? However, I am just one of the two pilots of that thing."

"Neither I nor my partner plans to antagonise humanity; we just want to study this world at our leisure pace."

Those might be simple words to him.

However, to them, it was like saying, "Don't piss me off, or else I'll destroy the world."

A statement so simple yet held lots of meaning behind it.

[Mitsuya-san. Can I learn under you? You know a lot more, don't you? And your powers, I had planned on asking, can I?

Saying that, Mitsuya had looked over her and thought of it for a moment.

And yes, now that he thinks of it. Perhaps this is the best time.

"Alright."

Through this, he can come into possession of a core, and even if not possession, at the very least, Navi can study it.

'Am I right? Navi?'

[It is as master says :3]