Gilgamesh's thoughts roared like a storm.
Did they really think he was a child? That he could be threatened so easily? As if he would ever cooperate for the sake of some petty Noble Phantasm. His purpose was to cleanse this rotten world, not bargain like a cornered animal.
And yet, when his lips parted, the answer came out anyway.
"…Fine."
"Still planning to resist?"
With Gilgamesh dealt with, Rowan Mercer turned his gaze toward the remaining man. Kirei Kotomine stood nearby, his posture calm, his expression empty. After a moment, he shook his head.
"There's no chance of victory," Kirei said quietly. "It's only a shame I couldn't finish what I started."
He had just witnessed Rowan withstand the full force of Gilgamesh's world-rending sword without so much as a scratch. That alone placed this mage in a realm far beyond anything Kirei had ever known. Even the head of the Clock Tower would have been helpless in front of that power.
There was nothing left to choose. Only death remained.
Kirei did not fear it. He had never feared death. What lingered was regret. Regret that his design would end unfinished, that he would never savor the culmination of it all.
"At least you know yourself," Rowan said.
He lifted a hand. The distorted mirror-world dissolved, returning reality to its original shape. Rowan stepped forward and placed his palm on Kirei's head.
Memories unfolded.
A lifetime passed in seconds.
Rowan saw everything. Kirei's childhood, his twisted nature, the Fourth Holy Grail War in its entirety. He learned the identities of the remaining Masters. And then, something unexpected surfaced.
"So that's it," Rowan murmured. "You modified the Command Seals. Enough to bind two Servants at once."
At the end of the Fourth War, Kirei should have died. Kiritsugu Emiya had shot through his heart. But when Gilgamesh was tainted by the Grail's corruption and gained a physical body, the blackened mud flowed backward through their contract, filling the void in Kirei's chest and restoring his life.
After the war, with the Greater Grail gone and no longer supplying magical energy, Kirei used the Church as cover. He took in orphans.
In truth, he sacrificed them, one by one, to sustain Gilgamesh.
During that time, he refined the Command Seals. He pushed the system beyond its intended limits. By the start of the Fifth War, he had already prepared a method to contract a second Servant. He ambushed and killed Lancer's Master, taking control for himself.
That knowledge alone was priceless.
But Rowan went further.
As he finished scanning Kirei's memories, new structures were already forming in his mind. The ritual logic unraveled itself cleanly, like a solved equation. A redesigned Command Seal capable of sustaining seven or eight Servants simultaneously emerged almost instantly.
Given time, binding hundreds would not be impossible.
"Command Seals. Transfer."
Rowan tapped Kirei's arms. The two Command Seals burned briefly, then tore themselves free, streaming into Rowan's right hand. They merged seamlessly with the seal already engraved there, the one tied to Artoria.
Rowan immobilized Kirei with magic and turned to Rin Tohsaka.
"There's bad news," he said calmly. "The Holy Grail is already corrupted. Even if you win this war, no wish can be granted anymore."
Artoria stiffened behind him.
"So… will you hear a proposal?"
As he spoke, Rowan transmitted everything he had learned about the Fourth War.
The Third Holy Grail War had gone wrong long before. The Einzbern family had summoned an irregular Servant, Angra Mainyu, a being meant to embody all the world's evils. Ironically, it had been weak. Barely stronger than an ordinary man. It died four days into the war.
Its soul was absorbed into the Greater Grail.
The Grail's neutral, formless energy was tainted. Twisted into a curse. Black mud born from a wish for evil.
From that point on, the Grail could no longer grant wishes.
The war itself had never truly been about wishes anyway. It was a ritual. A method to approach the Root. The so-called "wish" was only a byproduct, made possible because the Grail gathered vast amounts of raw magical energy. Enough to fulfill many desires, though never truly impossible ones.
But now that energy was gone. Replaced by corruption.
"No wonder…" Artoria whispered.
Her expression dimmed. At last, she understood why Kiritsugu Emiya had ordered her to destroy the Grail despite achieving victory in the Fourth War. If the ritual had been completed, the corrupted mud would have poured into the world and erased humanity itself.
And that meant something else as well.
Her wish to rewrite Britain's history had never been attainable.
"So the fire…" Shirou Emiya said softly.
Kiritsugu had ordered the Grail's destruction. The black mud was stopped, but Fuyuki burned. Everyone Shirou loved died that night.
After a long silence, his expression steadied. If that order hadn't been given, it wouldn't have been just his family that died. It would have been everyone.
Nearby, Illyasviel finally understood as well.
"So that's why…" she murmured. "He adopted Shirou out of guilt. And he didn't come back because the family forbade it."
Her father had not abandoned her. He simply had no choice.
"What's the deal?" Rin asked.
She had processed everything now. With the Grail rendered meaningless, there was no reason for the war to continue.
Rowan casually tossed Kirei's frozen body at her feet.
"I give you the man who murdered your father. What you do with him is your choice. Kill him. Spare him. That's up to you."
Rin's fists clenched.
"In exchange," Rowan continued, "you transfer your Command Seals to me."
He could have taken them by force. Easily. But Rowan preferred clean transactions when violence wasn't necessary.
Rin didn't answer immediately.
"If the Grail War is already over in spirit," she said carefully, "why do you still want my Command Seals?"
"Because I was never here to make a wish," Rowan replied. "The Grail can't grant what I seek. I want to understand the ritual itself. To decipher the true magic behind it and find a legitimate path to the Root. That's what magi were always meant to pursue."
He wasn't lying.
Before reaching that destination, though, there was plenty to learn. Noble Phantasms. Magecraft systems unique to this world. Knowledge worth harvesting.
Rin inhaled slowly.
"…Fine. I accept."
She trusted him. After witnessing his battle with Gilgamesh, she knew he could have erased her at any moment. A deal was unnecessary unless he genuinely meant it.
And without Rowan, she and Archer would never have survived against Kirei and two Servants.
"Good."
Rowan turned away.
"Take care of things here. There are still children in the basement. Save them. I'll go collect the remaining three sets of Command Seals."
With that, he vanished, leaving the ruined battlefield behind.