The golden light gradually disappeared.
What remained afterward was a complete mess.
The place where Valefor and his Queen stood earlier was simply gone, leaving behind melted ground and a gigantic hole that pierced straight through the cave ceiling. Cold night air slowly flowed inside while the stars above became visible from underground.
For a moment, nobody spoke.
Even Artoria quietly stared at the destruction left behind by Excalibur.
Then Ren suddenly clapped his hands.
"Well… that was one hell of a finisher."
Artoria slowly lowered her sword before looking toward him.
"…Thank you for your assistance."
"If you and Aesc had not helped earlier, this battle would have been much harder."
Ren waved his hand casually.
"Don't worry about it. Helping people and Cleaning up dangerous stuff is basically my full-time job at this point."
Then he looked toward Kiritsugu.
"So? Do you trust me now?"
Kiritsugu stayed silent for a few seconds.
Honestly, he still didn't fully trust Ren.
But after tonight, completely dismissing him was impossible anymore.
Ren had been right about the devils.
Right about other factions targeting the Grail.
And right about the ambush waiting inside the cave.
Kiritsugu let out a quiet breath.
"…A little."
Beside him, Artoria nodded slightly.
"At the very least, we now know your warnings were genuine."
Ren grinned faintly.
"I'll take that."
Kiritsugu then looked back toward the Greater Grail again.
"…Even so, I still want to communicate with it."
Artoria glanced at him quietly but didn't interrupt.
Surprisingly, Ren didn't stop him either.
"Sure," he said simply.
Then his expression became a little more serious as he looked toward the Grail.
"But before that… there's something you should know."
"I don't know if the Einzberns ever told you this, but they made a huge mess during the previous Holy Grail War."
Kiritsugu frowned slightly.
"What do you mean?"
"They summoned a Servant Class that wasn't supposed to exist in the system," Ren answered. "Avenger-Class, His name Angra Mainyu"
Artoria's expression shifted slightly after hearing the class name, but Kiritsugu only looked confused.
Ren noticed immediately.
He explained more casually. "Normally the Grail summons heroes, kings, warriors, people with legends behind them."
"But Angra Mainyu was different."
Ren glanced toward the Grail for a moment.
"That guy wasn't some famous hero. He was basically a vessel for humanity's hatred and curses."
"During the previous war, the Einzberns summoned him as an Avenger-Class Servant."
The cave became quiet again.
"Then he died," Ren continued. "Honestly, the guy himself was really weak."
"like every other Servant, his soul still returned to the Grail system after death."
Ren's expression became slightly more serious.
"And that's where the problem started."
"Remember what I told you a moment ago? He was basically a container filled with humanity's hatred and curses. He is the source of all evil in the world"
"So when his soul returned to the Grail…"
Ren quietly looked toward the Greater Grail.
"…all of that 'All the World's Evil' returned with him and ended up inside the Grail itself."
Kiritsugu slowly started understanding what Ren was trying to say.
"…So you were saying, that thing affected the Grail?"
"Probably," Ren replied with a small shrug. "At least, that's what I think."
He looked toward the Greater Grail again.
"Right now it still looks normal from the outside, so even I can't tell how bad it is yet."
Then Ren glanced back toward Kiritsugu.
"But if you're really going to communicate with it…"
His tone became more serious.
"…don't just believe everything it shows you."
Kiritsugu nodded then slowly stepped toward the Greater Grail.
Behind him, Artoria silently stood guard while watching the surroundings carefully.
Meanwhile, farther behind them, Ren and Aesc quietly observed everything.
Ren suddenly glanced toward Aesc.
"…Do you see anything?"
Aesc narrowed her eyes slightly.
With her Fairy Eyes, the Grail looked different from normal.
At first glance, it still appeared stable.
Normal.
But buried deep inside—
Something was there.
A faint darkness.
A hint of malice.
Tiny from the outside, yet deeply rooted, like a nest of greenskins waiting to burst open one day and scream "WAAAGGH!" as they dragged everything into chaos.
Aesc's expression gradually became more serious.
"…There's definitely something inside."
Ren nodded slightly.
"See, I wasn't lying."
Then, without another word, he casually opened a portal beside him and pulled out three swords.
Gilgamesh's treasures, more specifically, the ones Ren had stolen yesterday.
Ren placed the three swords onto the ground before taking out his usual pen again.
Then he started drawing Three Thaumaturgic Symbols onto each blade one by one.
Aesc quietly watched from the side.
Two of the symbols were already familiar to her.
TS-381-V2 Kalaphastian Isle and TS-1817-V7 The Twelve Holy Owls of Serrinithium.
Ren used those two on his gun
But the third symbol—
That one she didn't recognize.
The symbol itself looked strange compared to the others, almost resembling countless overlapping eyes.
it actually symbol called TS-2201-V1 Unnamed, A symbol originally used alongside telescopic devices to detect psionic entities carrying malicious intent toward the user.
Even though Aesc didn't know what the last symbol do, but she understood the function the other two.
What Aesc didn't understand was why Ren was engraving those symbols onto swords in the first place.
Was he expecting another enemy?
Meanwhile Ren continued drawing calmly.
After finishing the last symbol, Ren walked around the Grail then stabbed the three swords into the ground around the Grail in a triangular formation.
Artoria noticed it immediately and looked toward Ren in confusion, but she didn't stop him.
Ren returned to Aesc's side, only to find her looking at him with almost the same confused expression as Artoria.
"Confused?" Ren asked casually.
Then, out of nowhere, He pulled out a blackboard and started tapping it with a stick.
Tap tap
"Ahem Attention Please! Let me, Ren-sensei teach you something about these symbols"
"These three Thaumaturgic Symbols are called Kalaphastian Isle, Twelve Holy Owls of Serrinithium, and Unnamed."
"These three Symbols Represent Protection. Isolation. Containment" Ren explained while tapping the blackboard.
"Link them correctly and they become a barrier. Or a seal, depending on how you use them."
He glanced toward the swords planted around the Grail.
"And all three of them come from the same entity."
"The Star."
"The Hateful."
"Or as the Foundation calls it… SCP-1548."
Aesc then watched the symbols faintly glowing on the swords before slowly looking toward Ren, who was somehow already wearing a teacher uniform while seriously explaining the lesson.
Ren ignored her questioning gaze and continued.
"SCP-1548 is a Keter-Class entity, but unlike most Keter-Class anomalies, it doesn't really hate humanity. If anything, it's doing the opposite."
Ren looked up toward the stars visible through the massive hole above the cave.
"SCP-1548 itself is a phenomenon connected to the Sun. On the surface of the Sun, these three symbols constantly appear and disappear like they're flickering."
He pointed toward the symbols engraved onto the swords.
"The Foundation believes those symbols are part of a massive barrier SCP-1548 uses to protect the Solar System from things outside."
Aesc then looked toward the three swords surrounding the Grail, quickly understanding Ren's intention.
"So Ren, this time..."
cough
Ren suddenly interrupted her with a smug look.
"What should you call me again?"
Aesc stared at him silently for a few seconds.
Then she sighed.
"…Sensei."
Only then did Ren nod in satisfaction.
Aesc continued with a tired expression.
"So you're using those swords as carriers for the Thaumaturgic Symbols..."
Aesc looked toward the three blades surrounding the Grail before narrowing her eyes slightly.
"You're planning to seal the Grail"
Ren smiled faintly before giving her a thumbs up.
"Correct! Here, a little star for you."
"…Ah, right."
Aesc glanced toward him.
"What?"
Ren extended his hand toward her.
"Give me your hand for a second."
Although puzzled, Aesc still did what he asked.
The moment Ren held her hand, a strange sensation immediately flowed into her body.
Aesc's eyes narrowed slightly.
It wasn't mana nor magical energy. The energy felt… different.
Unfamiliar.
More unstable somehow, yet at the same time carrying an overwhelming sense of distortion.
Aesc immediately looked toward Ren.
"What did you just transfer to me?"
"Thaumaturgy Energy," Ren answered casually.
Aesc blinked slightly after hearing that.
Ren then continued
"I almost forgot about it earlier. You see even if your original self agrees to come down from the Throne of Heroes later, simply drawing the symbol I gave you won't do anything by itself."
Aesc quietly listened.
"To use Thaumaturgic Symbols properly," Ren explained, "you either need to be the original source of the symbols…"
"Or possess enough Thaumaturgy Energy to imitate and activate them."
"So I transferred some to you beforehand."
"Without Thaumaturgy Energy, those symbols are basically just graffiti."
Aesc could still feel the unfamiliar energy flowing slowly inside her body.
"…This energy feels dangerous."
Ren immediately nodded.
"Oh, it absolutely is."
"After all, every Reality Bender uses this kind of energy."
Then his expression became a little more serious.
"But remember one thing. You can only use it for the Thaumaturgic Symbols I taught you. Don't try using it for anything else."
Aesc noticed the subtle warning in his tone immediately.
In truth, what Ren transferred to her wasn't Thaumaturgy Energy originating from Reality Bender power.
It came from SCP-001 Keter Duty.
Ever since merging with part of Keter Duty, Ren himself had become something similar to a living source for Thaumaturgic Symbols. Because of that, he could share a portion of the Thaumaturgy Energy originating from Keter Duty with other people, allowing them to draw copied symbols connected to him.
But that was the limit.
They couldn't use the energy for something else.
They could only use it to draw Thaumaturgic Symbols connected to him.
Nothing more.
Aesc slowly looked at her own hand again "…Understood."
===
Meanwhile inside the Holy Grail Space
The moment Kiritsugu touched the Grail, the world around him changed.
The cave disappeared. The cold wind vanished. Before he realized it, he was standing inside endless darkness once again.
"…So this is the inside of the Grail."
Then light slowly appeared before him.
A woman stood there quietly.
White hair. Red eyes.
Irisviel?
No, it wasn't her.
Kiritsugu narrowed his eyes slightly.
"You are the ancestor of the Einzbern… Justeaze."
The woman smiled gently.
"Welcome, Kiritsugu."
Her voice sounded almost identical to Irisviel's, yet strangely hollow at the same time.
Kiritsugu silently looked at her for a few moments before speaking.
"So this is the Grail."
"In a sense," Justeaze answered calmly before slowly walking closer toward him.
"You wished for world peace, did you not?"
Kiritsugu's expression remained unchanged.
"…Yes. No more wars. No more meaningless sacrifices."
Justeaze tilted her head slightly.
"And how have you pursued that wish until now?"
Kiritsugu answered immediately.
"By sacrificing the few to save the many."
It was the method he had followed his entire life.
Cold. Cruel. But efficient.
Justeaze quietly nodded.
"Then the Grail shall grant your wish through the method most familiar to you."
The darkness around them suddenly changed.
Visions began appearing one after another.
A sinking ship appeared in the dark sea.
People screamed desperately while the ship slowly collapsed into the sea.
Then Justeaze spoke calmly.
"Only half the lifeboats remain."
Kiritsugu's expression hardened immediately.
He already understood the answer.
"If the ship becomes overloaded, everyone dies."
So he abandoned part of the passengers.
The vision changed instantly.
This time, it was a city consumed by war and disease.
Corpses filled the streets while infection continued spreading endlessly.
"To save the city," Justeaze asked quietly, "what should be sacrificed?"
Kiritsugu answered without hesitation.
"The infected area."
The next moment, the entire district was engulfed in flames.
Thousands died.
But the rest survived.
Again.
Again.
Again.
The visions continued escalating. Each time the answer remained the same.
Sacrifice fewer people to save more.
The scale kept growing larger. Each time the answer remained the same.
Kill fewer people to save more.
Until eventually, Kiritsugu saw mountains of corpses stretching endlessly before him. Entire cities erased. Countries destroyed.
And at the very end—
Only a small number of humans remained alive.
Justeaze calmly looked toward him.
"This is the answer your wish arrives at."
Kiritsugu's expression slowly darkened.
"No… this is impossible."
"The Grail merely follows the path inside your heart," Justeaze replied calmly.
Then something beneath the darkness began moving.
Black mud slowly spread across the ground.
An overwhelming amount of hatred and curses flooded the space instantly.
The moment Kiritsugu sensed it clearly, Ren's words resurfaced inside his mind.
"All the World's Evil…"
His expression changed completely.
The thing inside the Grail was corrupted.
No—
It had already become something monstrous.
Kiritsugu immediately stepped back.
"I reject this."
The darkness distorted violently around him.
Then the next moment, Kiritsugu suddenly opened his eyes back in the real world.
The cave entered his vision once more.
Artoria immediately noticed his expression.
"…Kiritsugu?"
But Kiritsugu ignored her completely.
His face looked darker than ever before.
Then he shouted immediately—
"Saber!"
Artoria stiffened slightly.
"Destroy the Grail."
Hearing those words, Artoria's eyes widened slightly.
"Destroy the Grail…?"
Her voice carried clear disbelief.
Even after hearing Ren's warnings earlier, a part of her still held onto hope.
Hope that the Holy Grail truly existed as the miracle she had been searching for all this time.
She immediately stepped toward Kiritsugu.
"Explain yourself, Kiritsugu!"
"Why would you—"
But before Kiritsugu could answer—
The Greater Grail suddenly trembled violently.
A thick black substance slowly began overflowing from the surface of the Grail.
Black mud.
The moment it touched the ground, the surrounding mana immediately became twisted and heavy.
An overwhelming amount of hatred and curses flooded the cave instantly.
Even the air itself felt wrong.
Artoria froze.
Her instincts screamed at her immediately.
This thing—
Was dangerous.
Kiritsugu's expression darkened further while staring at the black mud spreading across the floor.
"…That is the true form of the Grail."
Silence filled the cave.
Artoria slowly tightened her grip on Excalibur.
The answer was already right in front of her.
Even without Kiritsugu explaining further, she understood now.
The Grail she had pursued until the very end—
Was nothing more than a cursed disaster.
Her chest tightened painfully.
Years of hope.
Years of regret.
All of it—
A lie.
For a brief moment, anger and grief flashed across her face.
But in the end, Artoria slowly closed her eyes.
Then she raised Excalibur once more.
No matter how painful it was—
She still had to do what needed to be done.
Ren remained silent.
He didn't stop Artoria.
In fact, this was exactly what he needed.
The Grail had to be damaged first.
If he sealed it completely while it was still intact, then Artoria and Aesc would remain tied to the Grail system itself and eventually be dragged back.
So first—
The connection needed to be broken.
Then it could be sealed.
Artoria slowly raised Excalibur once more.
Golden light began gathering around the holy sword as the cave trembled violently from the overwhelming mana.
This time, her expression looked far heavier than before.
Not anger.
Not hesitation.
Only disappointment.
Then she began chanting quietly.
"——Excalibur."
The golden light exploded instantly.
Boom!!!
The holy beam slammed directly into the Greater Grail.
For a brief second, everything turned white.
Then cracks began spreading across the Grail itself like shattered glass.
And the next moment—
Black mud burst out violently from the cracks.
Far more than before.
It poured endlessly from the damaged Grail like a broken dam.
Artoria's eyes widened in horror.
"How much hatred is inside that thing…?!"
The black mud rapidly spread across the cave floor while countless curses flooded the surroundings.
Even Kiritsugu's expression became ugly.
But then—
Ren finally moved.
"Alright. My turn."
The three swords he planted earlier suddenly trembled.
Then all three shot into the air at the same time.
Clang!
Clang!
Clang!
The swords positioned themselves around the Grail in a perfect triangle.
The Thaumaturgic Symbols engraved onto them began glowing brightly.
Blue light.
Black light.
Golden light.
The symbols resonated with each other instantly.
Then a massive seal suddenly appeared around the Grail.
Buzz—
The surrounding space distorted violently.
The overflowing black mud abruptly slowed down.
Then stopped completely.
The curses inside the Grail were forcefully suppressed back inward as the sealing field tightened around it.
Even the cave itself became quieter afterward.
For a few moments, nobody spoke.
Then Kiritsugu slowly let out a long breath.
"…It stopped."
Artoria also lowered Excalibur slightly while staring at the sealed Grail silently.
Beside them, Aesc quietly looked toward Ren.
Meanwhile Ren himself simply stretched his shoulders casually.
"See? Problem solved."
=====================
Author's Note:
I reread some of the previous chapters and noticed a few comments mentioning confusing parts. Then I realized I forgot to properly explain certain things, like whether Ren merges with SCP traits or actually summons the SCPs themselves. Hehe, my bad. I'll fix and clarify those parts later.
Also, if you notice any confusing or inconsistent parts, feel free to point them out in the newest chapter and mention it like this:
Chapter Number — The Problem
If you comment on older chapters, there's a high chance I won't notice it since this fanfic is already 30 chapters long.
Anyway, Thank you so much and I hope you like the fanfic.