Naturally, the first one to speak was Gilgamesh.
"The den of worms, the central plaza… and the mongrel's manor."
It was a sentence where even the personal pronouns weren't properly addressed, yet everyone understood exactly where he meant.
The Matou residence, the Fuyuki Citizen's Hall in the center of the city… and Tokiomi's Tohsaka residence.
"Hurry! We must evacuate those not yet caught in this catastrophe!"
Golden ripples shimmered in the air as a massive, ship-like vessel emerged. Iskandar likewise summoned his great chariot, pulling Waver aboard before charging forth.
Boarding the Vimana and looking down at Fuyuki City from the sky, the scene was nothing short of horrific.
Burning, mud-like sludge was prowling the city streets, birthing grotesque creatures similar to the Berserker from earlier as if casting them from molds. The fires that had begun to rage near the Citizen's Hall were swelling in size along with the mud, slowly eroding the urban landscape.
"To force this King to use his Noble Phantasms against such insignificant wretches that don't even qualify as mongrels…!"
Lightning discharged from Iskandar's chariot and magical bombardment from the Vimana's turrets crushed the mud, but the sheer volume of the overflowing sludge was overwhelming—it was like trying to block a river with one's palms.
At that moment, a thought struck me.
"King Gilgamesh, you head toward the Tohsaka residence!"
"What? You dare command this King?"
"It's not that! I've thought of a way to handle this!"
There were three locations where the mud was surging from.
The original site of the Greater Grail at Ryuudou Temple had been transferred by Gilgamesh into the Great Cup of Uruk, but the mud had somehow reappeared at the Tohsaka manor, the Fuyuki Citizen's Hall, and the Matou manor.
And those three locations, along with Ryuudou Temple, were the concentrated nodes of Fuyuki City's Leylines.
"It means Angra Mainyu is moving through the Leylines."
"…I see. So if we sever the Leylines themselves, we only need to clean up the mud that's already surfaced!"
The mud was being continuously 'generated,' fueled by the prana supplied by the Leylines.
In other words, if we destroyed the sources, we would only have to deal with the remnants.
"We need anti-fortress Noble Phantasms here… Saber, you take the Fuyuki Citizen's Hall. You can blow away the source of the mud with 'Excalibur,' right?"
"Understood. However, if we do that… the Matou side remains."
Among those present, only the King of Knights with Excalibur and the Wise King with his endless treasury possessed the firepower to excise an entire Leyline node.
Iskandar's Reality Marble wasn't suited for pinpoint destruction of a source, and Assassin, who was currently assisting with evacuations elsewhere, was a Servant strictly specialized in anti-personnel combat.
"…I shall go," Lancer declared.
"No, that is an Evil of Humanity. Even your incurable curses would simply be overwritten by it."
"If it is a matter of excise a Leyline, my Gae Dearg might be effective."
"The prana-severing effect…"
But would it be possible to stop Angra Mainyu, who was flowing through the Leylines, with a single spear?
As I hesitated, someone grabbed me firmly and began pulling me along.
"You'll never know until you try anyway. Why are you just standing there?! Hurry up!"
"…Dammit, I guess there's no choice…!"
* * * * *
As we descended to the ground, the chaotic state of Fuyuki City came into full view.
The majority of the citizens were fleeing in panic, and the slow-moving sludge spat out grotesque doll-like mud monsters that lunged at the people.
"[Shinra Tensei]!!!"
Aside from Waver, whose lack of skill forced him to stay close to a Servant to provide prana, all remaining Masters were busy running through the city saving people. The Servants were also divided into teams, either rescuing citizens or moving toward the suspected sources.
The most prominent was the Assassin, Hassan of the Hundred Faces. Nearly eighty doubles moved with perfect coordination, guiding citizens and intercepting the mud monsters with thrown dirks.
When we were halfway to the Matou manor, a red light suddenly flashed near Ryuudou Temple in the distance, followed by a thunderous roar that made the very atmosphere tremble.
"Good grief, the Wise King didn't pull out the Sword of Rupture, did he?"
"…For now, let's focus on our task."
The Matou manor, which Aoko-nee had been observing, was already covered in mud and in complete shambles.
After blowing the gates open with a Magic Bullet and entering, the mud on the floor surged up like a living thing to attack us.
"Hup…!"
While I repelled them with Shinra Tensei and Aoko-nee used Magic Bullets and flame magecraft, Lancer cleaved through the mud using only his spear technique. We charged forward until something blocked our path.
A man with familiar seaweed-like hair and the face of the 'Matou family,' yet a face slightly different from what I knew.
"Byakuya Matou…"
"The current head of the Matou family. Out of the way!"
Whether he had already been swallowed by the mud or had simply lost his mind, he lunged at us, only to be hammered by Aoko-nee's Magic Bullets and pierced by Lancer's red spear.
"I have severed the path connected to the mud… but in that state, I doubt he will last long."
"…Wait. Halt."
"Is something there?"
The chilling sensation I had felt earlier at Ryuudou Temple was intensifying.
The sensation of death—a thrill I had learned from my fight with Beowulf—was prickling my skin with a warning.
Directly beneath us, in the basement, there was something 'extremely dangerous.'
The mud that had surrounded us suddenly sank into the ground as if absorbed, and after a brief look at each other, Aoko-nee and I both sighed.
"…That means we have to go down to the basement."
"No avoiding it, then."
Aoko-nee fired a Magic Bullet to blast a massive hole in the floor, and Lancer was the first to leap in.
Aoko-nee and I followed in order…
"…Oh, god."
The scene inside was a literal hellscape.
A handsome, middle-aged man with a striking resemblance to Byakuya Matou was there.
However, even an ordinary person could tell his physical condition was dire. His right arm was stained pitch black, as if eroded by mud, and his left leg was grotesquely twisted as if it had been passed through a hydraulic press.
His right eye was more than just crushed; it dangled half out of its socket, clearly blind. Bloody tears streamed from his remaining eye, and blood flowed from his mouth.
And to top it off, standing before him was a white-haired, red-eyed woman in a revealing dress.
[Uninvited guests have arrived, my dear friend.]
"Begone… you are not my friend!"
I knew who they were.
Both of them were people I recognized.
Though their appearances differed from what I knew, I could confirm their identities through the 'setting.'
"Karma, is that…?"
"Matou… no, Makiri Zolgen. And the other is…"
Justeaze Lizrich von Einzbern.
The woman who was sacrificed and crushed at the altar of the Greater Grail, the perfect homunculus who inherited the Third Magic from the original Third Magician.
"It's something else, wearing her skin."
Just as it had tried to bait Kiritsugu Emiya in the original 4th Holy Grail War using Irisviel's body, it was now using her form to attack Makiri Zolgen, who had regressed to his past self.
[Yes, it is you. Child.]
The moment I looked at it—at 'Angra Mainyu'—it looked directly back at me.
[By rights, I should not have been able to manifest. So how is it that I am standing here…?]
"Does it matter?"
I quickly tried to blow off its head with Shinra Tensei, but the mud instantly regenerated its torso and spoke.
[As long as humanity harbors retribution in their hearts, I shall never die. Envy and hatred are the very nourishment for this body. Did you truly think even Heroic Spirits were free from that Truth?]
"Shut up."
While Aoko-nee rapidly fired Magic Bullets, I crossed my thumbs and formed a hand seal.
"Come forth, Naraka Path!"
A colossal head in the image of King Enma appeared, opening its mouth wide to snatch Makiri Zolgen with its tongue.
"What is this—!"
"Just stay in there for now. I can't have you dying yet!"
[Futile efforts. Do you think you can stop me just because Matou Zouken has returned to his past form?]
"No, I just need this guy later. You, on the other hand, I don't!"
Using the prana I had charged in advance, I transformed my body into the Asura Path. While Aoko-nee kept the Justeaze-shaped mud at bay with her Magic Bullets, I began tearing the basement apart.
"Diarmuid, find the convergence point of the Leylines! You have to pierce the source and destroy it!"
"Ugh, I shall do so!"
[Useless. Even if I haven't fully manifested, I am still an Evil of Humanity. Do you think the Fifth Magician's True Magic will suffice?!]
"Then try a taste of the Origin!"
Since the Animal Path risked the beasts being swallowed by mud and the Human Path was useless here, I simply used Bansho Ten'in to hold the swarming mud in place.
Aoko-nee, her hair now glowing a vivid crimson, rained down bowling-ball-sized Magic Bullets to shatter the mud. Lancer sifted through the sludge throughout the basement with his spear, searching for the source of the prana.
"Gah, seriously… Karma! Can't you find the source with your eyes?"
"If it were that easy, I'd have found it already! Dammit, this beast is blocking my sight!"
Blocking the encroaching mud was reaching its limit. I had no choice but to start absorbing the prana stored in the Mystic Codes I had borrowed from Alice.
At that moment, I heard Diarmuid cry out from a corner.
"I've found it!"
"Good, pierce it!"
Immediately after, the mud convulsed violently. I blew away the mud I was holding with Bansho Ten'in and shifted back into the Asura Path.
But then, the mud that had been scattered haphazardly began to vibrate, gathering in one place and emitting a blinding light.
"What is that? Don't tell me it's going to self-destruct?!"
"…Could it be?"
Bubbles seethed within the mud, and soon, a massive circular magic circle appeared.
"Diarmuid!"
"Yes!"
Diarmuid lunged forward and shattered the circle with his red spear, but dozens more magic circles were already appearing around us.
Aoko-nee and I joined Diarmuid in smashing them. Though I didn't fully understand the formula as someone with little formal training, it was obviously an enemy construct, and therefore dangerous.
However, the creature opened its mouth, and I realized what those circles signified.
[Did you think only you could make use of the Throne of Heroes? The Greater Grail is already in my hands!]
Immediately, the summoning circles flashed, and dozens of 'Black Servants' began to pour out.
* * * * *
"Urgh…!"
"Diarmuid!"
The first to fall was Diarmuid.
Taking advantage of the gap while I used Bansho Ten'in to restrain the mud, Diarmuid had quickly intercepted an Assassin rushing toward me. But in the next second, his back was pierced by the long sword of 'Siegfried,' a swordsman with a fully exposed torso. Diarmuid collapsed into the mud and began to be absorbed.
"Please… save my Master…!"
As a final act of desperation, he hurled Gae Dearg toward me before being completely swallowed by the darkness.
Lancer's elimination was a tragedy, but grieving was a luxury we couldn't afford.
"Dammit, are all of these Heroic Spirits?!"
"The one with the sword on the far right is Siegfried! The one with the bow is likely Atalanta, Aoko-nee!"
"They're Heroic Spirits, so they should be fine with a few injuries!"
Aoko-nee sent her crimson-dyed hair floating into the air and shouted with a sharp voice.
"Exchange Connection—One Week!"
"…To hell with it. Destroying the source is impossible like this…!"
As Aoko-nee began using her Magic, the Servants summoned by Angra Mainyu began to be pushed back. I took the opportunity to search for the source among the thinning sludge.
"◼︎◼︎◼︎◼︎◼︎◼︎◼︎!!!"
"Don't you dare lay a finger on my little brother, you trash!"
Our raw firepower was superior, yet the situation was turning sour.
Aoko-nee's Fifth Magic was explicitly restricted by the World, and that damn Alaya was placing constraints on the Magic regardless of whether an Evil of Humanity was running amok.
[It is useless. Why do you struggle?]
"What?"
[I am a catastrophe. I am retribution. I am an inevitable existence. Why do you fight me? No one seeks revenge against fate because they died in a natural disaster. Before I am an Evil of Humanity, I am an Avenger. I am the beast that resents vengeance; your grudge is nothing compared to mine!]
Even so.
"What a load of bullshit."
[What…?]
"Then why didn't you just stay dead in that cave?"
[…]
"Stop the nonsense, Beast. Your original self—the 'youth'—forgave everyone before he sought revenge. You're nothing but a beast wearing the skin of that forgiveness, playing the part of pure evil."
[…Fine. Then struggle as much as you like. You can do nothing! What of Magic? What of the Origin? You are but a pathetic animal that cannot even find my source!]
Inflating its body like the Thames Troll, it suddenly blanketed the surrounding space and began projecting illusions.
[Behold, the fate of those you believe in!]
Wretched scenes flickered into view.
The first was Kirei Kotomine murdering Assassin and slaughtering civilians.
Then followed Waver being swept away by mud, Kayneth being stabbed by a mud-corrupted Sola-Ui, and finally, Kiritsugu Emiya pushing an entire family into the mud to save his own wife.
[Life has no meaning. Why do you fight! Did you believe in your allies? No Heroic Spirit—not even the primeval King of Heroes you trust—can throw off my mud!]
"That might be true. If what you're showing me were real."
In truth, I should have anticipated this from the start.
Why did an Evil of Humanity wake up? Angra Mainyu should have been a Beast that failed to manifest. His awakening now meant a variable had interfered.
And the biggest variable at this point was…
"You're talking about me, aren't you?"
[…]
"These false illusions prove it. I don't know why I caused you to manifest, but these visions clearly show you are lying."
A weak Waver Velvet swallowed by mud, Kayneth El-Melloi Archibald stabbed by Sola-Ui, Kiritsugu Emiya prioritizing his family above all, Kirei Kotomine killing Assassin and massacring citizens…
"None of these have happened in this timeline. In other words, none of them know this 'truth.'"
Perhaps the Wise King, with his sight across world-lines, might know, but I excluded him since his vision seemed limited for some unknown reason.
[It remains meaningless. If it is a future that hasn't happened, I shall make it so. All the mud in Fuyuki is in my hands. If you kill a hundred Heroic Spirits, I shall summon a thousand. Until this Leyline is dry and every soul is dead, my retribution shall not cease!]
Yes. This thing likely intended to do exactly that.
Unless Gilgamesh wiped the entire city with Ea, this persistent thing would escape Fuyuki to maintain its existence, becoming a true global disaster.
"The fact that you're desperately trying to hold me here means the other Servants are suppressing you. The Masters are excellent too. I'll place my bet on them."
Therefore, I would attempt my final gamble right here.
"[Six paths of existence. Hell, Asura, Preta, Animal, Human, and Deva. Cycle through each other, confront and complete.]"
As I chanted the incantation, Aoko-nee, who was battling the mud-covered Servants with her Magic, rushed toward me.
"Are you crazy? Don't you remember you almost died from prana exhaustion the last time you used that?!"
"[Preserve the principles of one another to fill the self; thus completing the immature one who has not attained enlightenment.]"
Alice-san taught me that the most important part of a magic performance is a single image.
Rin Tohsaka images stabbing her own heart to awaken her circuits; Shirou Emiya images the firing of a pistol.
My image was the opening of eyes.
Both my eyes shifted into the purple, ripple-patterned Rinnegan, and I felt my Magic Circuits heat up violently.
While the Rinnegan's abilities were normally instant, following Alice's advice to enhance their power, I had created special hand seals and specific formulas for certain techniques.
And for this 'impossible-to-activate ability,' I added the longest incantation in place of a special formula.
Prana surged from the hand I held with Aoko-nee like a rushing river, passing through my circuits and flowing out like a receding tide as I finished the chant.
"Ugh… this is seriously… even for me as a Magician, this is hard to bear…!!!"
"[Six Paths of Reincarnation. Supreme Enlightenment. Manifest.]"
Finally, as the chant concluded, a strange sense of weightlessness overcame me, and I saw a small black sphere floating in the air.
Excluding the techniques of the Outer Path that transcend the Six Paths, this was the strongest art—the pinnacle of sealing.
"Hidden Art—Chibaku Tensei!"