Chapter 57: After the Curtain Falls

My name is Illya.

Kariya owes me a life.

105:45:32

"I never imagined the King of Conquerors would run away so fast... I would love to see Lord El-Melloi II's expression upon meeting Emil. Kariya shouldn't die just yet, right?"

Having just wrapped up the utterly absurd Banquet of Kings, I returned to the Root to deal with the issue the prompt-sister mentioned: "Matou Kariya and Uryu Ryuunosuke might face life-threatening danger." As soon as I arrived, I saw Rider driving his Gordius Wheel straight into the Fuyuki Matou Mansion, with the newly captured little assassin girl sitting on his shoulder.

Meanwhile, Tohsaka Rin was staring wide-eyed, looking around in wonder from the flying vimana while constantly bombarding Gilgamesh with questions. The only response she received was, "You must be the mightiest Heroic Spirit, right?" "Hmph, obviously."

[He's fine for now. Matou Kariya is currently acting as a gracious host, treating Uryu Ryuunosuke to tea and conversation,] the foolish system Gaia replied.

*Oh, good then. There's nothing much to see regarding Gilgamesh; let's switch the surveillance feed to Rider.*

The foolish system spun half a circle in mid-air, projecting the live situation of the Matou Mansion from a giant globe.

"Little Waver, where have you been wandering off to again? And besides, who is she?" Sola-Ui's imperious, queen-like voice rang out before the image had even fully materialized.

"Please step back, Master, My Queen. She looks very much like an Assassin." Once the picture cleared, Sola-Ui and Kayneth were seen greeting Waver and Rider, who had descended from the sky in the Gordius Wheel. However, Diarmuid stood firmly between the two parties with a solemn expression, adopting a posture as if facing a formidable enemy.

Hmm... As expected, "Mind's Eye" is quite useful, instantly allowing him to determine who poses a potential threat.

"Uh, she is—"

"She's definitely Assassin!" Waver's words were cut short by Rider, whose attempt at a "defensive glare" carried zero intimidation.

"Rider, I expect a reasonable explanation," Kayneth stepped forward to demand, while Luvia, who had been tidying the courtyard grounds not far away, rushed over and assumed a defensive stance as well.

*I'd love to hear the justification for this kind of inviting a wolf into the house as well.*

"Well, you said you eliminated Assassin's infinitely divisible main body, right?" Rider lowered the little girl by her collar and set her down. "So, isn't every stray Assassin eliminated one less to worry about?"

"If we are to eliminate—"

"Let me finish."

Just as Lancer shifted the grip of his spear, Rider scooped Assassin behind his back with one arm.

"I encountered Caster while I was carrying her, and he was dragging Tohsaka Tokiomi's daughter along," Rider pointed in the general direction where we had held our cake-fueled Banquet of Kings.

"They must have been drawn by the pillar of light from Archer and Saber's clash," Kayneth immediately deduced the truth.

"Here's the crucial part: Tohsaka Tokiomi actually used a Command Spell to make Archer appear right beside us," Rider said in a deep voice.

"What? How is that possible? Under such unfavorable conditions, he should know we wouldn't harm non-combatants, which means—" Kayneth paused. "Which means, this Assassin is extremely important to them."

"Furthermore," Rider added, "Archer glared at this Assassin with a murderous expression the entire time, only turning his attention to Tohsaka Tokiomi's daughter after Caster left, taking her away as if to cover something up."

Wow, how come I missed all of this during the farce that was the Banquet of Kings?

"Therefore, Tohsaka Tokiomi doesn't care if she's killed; he simply cannot afford to leave her in the hands of a competent mage like Caster, otherwise 'something' might be exposed," Rider concluded, gazing expectantly at Kayneth.

*Hey... Exposed as what? Foolish system?*

[Exposed as the main body... Wouldn't that make things even worse?]

"Hah! Your judgment is sound, Rider. Whatever secret this Assassin carries, leave it to me, a prodigy of the Clock Tower!" Kayneth actually bought it. "Sola, you and Luvia can take charge of looking after and monitoring this Assassin, correct?"

"Heh, of course~ Come along with big sister~" Sola-Ui approached and took Emil's hand.

[Why does everyone want to be someone else's big sister—Whoa!]

*Cut the chatter, there's nothing left to see here, switch to the Matou residence.*

105:33:21

No matter what Matou Kariya imagined was waiting for him in his ancestral home, he was bound to be wrong.

Because even I didn't foresee that *this* thing would emerge.

When I switched the surveillance feed to the Matou residence, the underground worm pit was spotless, save for one entity—an Ouroboros? A Magma Chimera? Or maybe a Nalaseth? In short, it was a massive, upright, mutated giant insect.

It possessed heavy chitinous armor, razor-sharp arthropod limbs, and terrifying, crushing mandibles.

Meanwhile, Matou Kariya and Uryu Ryuunosuke, whose combat capabilities were clearly not on the same tier, were rummaging through the Matou mansion searching for magecraft inheritances, and it looked like they would soon head down to the basement.

*What on earth is that thing? Where did it crawl out from?*

[That... well, you were the one who threw it out with your own hands...]

*Huh? So that's—*

[Notice: Prototype 'PAX-201' is currently undergoing a special mutation state.]

Was that the Mana Wyrm snatched away by the old worm grandpa at the very beginning? I looked closely at the giant insect, but it had mutated so much its original form was completely unrecognizable.

*So what kind of special mutation state is this?*

[Because Makiri Zolgen decided to pack up and leave the Holy Grail War, taking all the other bugs with him except for this one, it had no 'symptoms' left to evolve with. Consequently, it spontaneously began evolving 'special abilities'. As for the specifics, I'll project them for you.]

Unlike "symptoms," "special abilities" could only be actively evolved rather than generated through autonomous mutation. Furthermore, they didn't trigger external physical signs like symptoms did, nor could they regress.

For instance, back when I was Patient Zero long ago, the "PAX-200" I contracted evolved traits like "Airborne Transmission," "Drug Resistance," and "Drought Adaptation," which fell under special abilities. However, those abilities were completely useless for this Holy Grail War, so I hadn't paid them any mind.

*Fine, show me what it secretly evolved.*

The foolish system spun around in mid-air and projected a glowing screen.

[Frenzy: Damage dealt increases proportionally when injured; damage bonus reaches 100% when health drops to 30%.]

[Rend: Inflicts bleeding upon dealing damage to enemies, incurable unless fully treated.]

[Gigantification: Maximum health increased by 40%, damage dealt increased by 30%.]

...This is no longer a matter of life-threatening danger! They are 100% dead!

"Kariya, why are all the Mystic Codes in your family meant for strengthening summoned minions?"

"Because our style inherently relies on summoned familiars for combat. After all, Command Spells were originally designed by the Matou family."

From another surveillance feed tracking Ryuunosuke and Kariya, they could be seen unearthing various Mystic Codes designed for enhancing and controlling summoned entities within the mansion, including armbands, bracers, and animal collars.

*Hmm... These are clearly Mystic Codes meant for small animals, raptors, and beasts, right? How come the old worm only ever used bugs?*

[Let me check...]

The red cube housing the foolish system spun in the air for a few moments, then suddenly recited in a deadpan, reading-from-a-script tone:

[Generations ago, Matou Zouken's summoned entities were numerous but lacked focus, leading to consecutive failures in early Holy Grail Wars. Eventually, he threw all controllable summons into an arena—now known as the underground worm pit—making them slaughter each other to determine which power to specialize in.]

*Did the bugs win a sweeping victory?*

[No. Actually, the entity that should have won was an avian raptor. It concealed itself skillfully and refused to strike without absolute certainty, thus surviving until the end alongside a swarm of numerically superior insects. Due to elemental counter advantages, its victory was practically guaranteed.]

*And yet?*

[And yet, the swarm of insects ultimately merged together and morphed into the exact shape of that raptor. This behavior deeply moved Matou Zouken, who was then pondering immortality, so he personally intervened to grant the insects ultimate victory.]

*...That hawk must have had some strong words to share.*

[Afterward, Matou Zouken began using insects as his avatars, replacing each successive head of the household upon producing an heir. This cycle repeated for twenty-six generations, causing him to completely forget his original wish of 'eradicating all evil in the world.']

*Thanks for reading the lore dump. Now tell me how to save Matou Kariya and Ryuunosuke.*

On the surveillance screen, Kariya was already heading down toward the underground worm pit. The two of them wouldn't even make a decent snack for that mutated giant insect.

*No, I have no idea, wuwuwu...*

*Useless foolish system—and now it's learning how to fake-cry.*

[Notice: Due to the influence of Prototype 'PAX-201's autonomous evolution, a portion of the Matou basement has undergone 'Otherworldification'.] The prompt-sister suddenly popped up a dialog box.

*Hmm... Otherworldification?*

Otherworldification meant isolating an area from the physical world, altering its environment and laws to favor the mage who initiated it, depending on their proficiency. The absolute pinnacle of Otherworldification was a "Reality Marble."

Clearly, that giant bug lacked the capability to initiate "Otherworldification" on its own, but since it was my creation, this otherworldified space was essentially—rooted in the Root in some sense?

I experimentally reached out and waved my hand across the screen displaying the giant bug. The colossal insect raised its head in response, its pitch-black compound eyes tracking the movement of my finger.

This feeling is just like... I curled my finger and flicked the giant bug on the projection screen. As a result, it recoiled backward as if struck squarely by an invisible force, then curled up into a ball looking thoroughly aggrieved.

It really is an electronic pet... In that case, can I directly interfere with the Root at least within the confines of the basement?

*Stop crying, you foolish system. I've thought of a way to save the two of them!*

I reached out, grabbed the red cube out of the air, gave it a couple of taps, and brought it right in front of the screen projecting the underground worm pit.

*You're going to create... then place it into..., and set it to... Got it?*

[Will this actually work? What if...]

*If there's a "what if," I'll unleash Caster on you! Hurry up and get to work!*