On a night in Fuyuki City, a discussion about alliance and cooperation was quietly taking place in the Matou Residence.

Kiritsugu Emiya, an experienced Magus, naturally felt vigilant and cautious when facing the unknown Master, Chen Yu.

Whether it was an alliance or cooperation, it was merely a mutual compromise based on their respective strategic interests.

If Saber's left hand had been perfectly intact, Kiritsugu Emiya naturally wouldn't have needed to consider an alliance or cooperation.

As a Saber of the Upper Three Knights in the Heroic Spirit system, her excellent stats were sufficient to handle most Servants.

As long as Saber could hold off the enemy Servant on the front lines, he would have multiple ways to contend with the opponent's Master.

But now Saber's left hand was crippled, her wrist cursed and unable to heal, and her skills were arguably only a tenth of what they once were.

As it stood, with Saber unable to remove the curse on her left hand, she was no match for Lancer or Berserker in a one-on-one fight.

Not to mention facing the even more mysterious and dangerous Archer.

With Saber's strongest noble phantasm unusable, seeking an alliance and cooperation was naturally a suitable choice.

However, as fellow competitors in the Holy Grail War, even in an alliance, one had to worry if the ally would stab them in the back.

But the fact that the other party could save Irisviel and Maiya from other Masters seemed to indicate a genuine desire to promote cooperation between them.

Yet, Kiritsugu Emiya's gaze was not fooled by the other party's superficial friendliness.

Kiritsugu Emiya glanced at Matou Kariya, who stood behind Chen Yu.

Before coming to Fuyuki City, Kiritsugu Emiya had already completed his intelligence gathering.

Aside from this Caster's Master, who appeared out of nowhere, he had already investigated most of the information on the other Masters participating in the Holy Grail War.

Especially the intelligence on the other two families besides the Einzbern Family, which was of paramount importance.

He naturally knew that the white-haired, gaunt, pale-skinned Matou Kariya with a deathly pallor on his face, who stood before him, was precisely the Master of Berserker who had just ambushed him.

As the second son of the Matou Family, one of The Three Families, he had resolutely left the Matou Family eleven years ago, abandoning magic to become an ordinary person who disliked magic.

But such a person, with no magical foundation whatsoever, became a Master capable of commanding a Servant in the year before the Holy Grail War began.

Kiritsugu Emiya did not know what exactly happened in that year, but from the decay on the man's face and body, he could tell how much the other party had sacrificed to participate in this Holy Grail War.

Yet, such a person, who had not hesitated to ruin his own body to participate in the Holy Grail War, now stood obediently behind the man before him, looking entirely subservient.

The hidden motives and power behind this made Kiritsugu Emiya re-evaluate the risks of this cooperation.

Berserker's two attacks on Saber further deepened Kiritsugu Emiya's suspicions.

Was this a test from Chen Yu's side?

To prove the value of their cooperation, did they need to demonstrate sufficient strength and determination?

Kiritsugu Emiya looked at Irisviel by his side again, and a hint of tenderness appeared in his dull eyes as he gazed at her.

After nodding slightly to Irisviel, he faced Chen Yu, who was not far away, and said, "We have no objection to forming an alliance, but since your side already has an intention to cooperate, could you please tell us why Berserker chose to attack our Saber twice? Both in the Warehouse District and tonight. Could this be considered a test from your side? To assess whether we have the capability to cooperate."

Chen Yu's face showed some surprise at Kiritsugu Emiya's question; he hadn't expected Kiritsugu Emiya's first question not to be about the corrupted Holy Grail, but something else.

He glanced at the nervous Irisviel and realized that Mrs. Emiya had not told Kiritsugu Emiya about the Holy Grail being corrupted outside the door.

However, as a thoughtful Master, he quickly adjusted his demeanor and replied in a calm and sincere tone, "Regarding Berserker's actions, I understand your concern. But please believe me, it was not at my command, but rather a spontaneous reaction based on Berserker's berserk state. As a Berserker among Servants, his rationality is not complete, and his actions are often unpredictable, leaning more towards seeking powerful opponents to fight rather than executing specific strategies."

Chen Yu explained, his tone revealing an understanding of Berserker's actions, while also expressing an apology to Kiritsugu Emiya and Saber.

"As for cooperation, I do indeed have that intention. The enemies we face together are not only other Masters and their Servants but also the unknown dangers brought by the Holy Grail War itself. My saving Irisviel and Maiya was not merely out of kindness, but based on a strategic consideration—an alliance allows us to have a greater chance of victory when facing more powerful enemies."

Chen Yu continued, his words frank yet not lacking in strategic foresight.

"The danger of the Holy Grail itself?"

Kiritsugu Emiya frowned; Chen Yu's answer was unexpected.

"It seems Mrs. Emiya hasn't had time to tell you about the Holy Grail being corrupted."

"What?" x2.

The corrupted Holy Grail—this news was like a thunderclap, shocking everyone present.

Kiritsugu Emiya and Saber exchanged glances, filled with shock and incomprehension.

They knew the cruelty of the Holy Grail War, but they had never imagined that the Holy Grail itself harbored such a great crisis.

"The Holy Grail is corrupted... Do you have proof?" Kiritsugu Emiya asked, his voice trembling slightly, but more so with a longing for the truth.

Chen Yu took a deep breath, his expression becoming serious.

"In the previous Holy Grail War," Chen Yu continued to explain, "this ritual of the Holy Grail War underwent a decisive, fundamental mutation. This was not as simple as a 'rule change,' but rather the greater grail itself was completely distorted due to corruption. The eighth class of Servant, Angra Mainyu, summoned by the Einzbern Family—a young man bearing all the evils in the world—was defeated early in the war, and his soul was absorbed into the Holy Grail according to the rules. His soul corrupted the Holy Grail, causing its functions to be maliciously twisted and amplified."

"In other words, the original Holy Grail, which should have been an omnipotent vessel to grant the victor's wish, did not lose this function after being corrupted; instead, it was imbued with endless malice. All wishes would proceed in the worst possible direction."

"If you don't believe what I say, you can investigate it yourself; I trust your ability to gather intelligence."

Hearing Chen Yu's words, Kiritsugu Emiya fell silent; he needed time to digest this news.

If what the other party said was true, that the Holy Grail was corrupted, it meant that all their efforts might ultimately come to naught, and could even lead to a greater disaster.

Thinking of this, Kiritsugu Emiya felt agitated and dry-mouthed.

Kiritsugu Emiya reached into his pocket, preparing to light a cigarette to calm down, when he suddenly thought of something and retorted, "If what you say is true, that the Holy Grail is corrupted, then why not seek cooperation from more Masters to prevent the disaster?"

Chen Yu pointed to Matou Kariya behind him, then to Kiritsugu Emiya, and said somewhat exasperatedly, "Isn't that what's happening right now?"

"Moreover, as a Magus Killer, you should understand the thoughts of Magi better than I do. Normal Magi don't care about the lives of ordinary people; as long as they can reach the Root and fulfill their long-cherished wish, whatever the cost is irrelevant to them."

"Let me give an example: if your old man Ahhad knew about the Holy Grail being corrupted, even if he knew that the descent of the Holy Grail would bring disaster to the people of Fuyuki City, would he stop for these people and give up the idea of recreating the Third Magic?"

Kiritsugu Emiya fell silent again, then with difficulty, uttered two words: "He wouldn't!"

As a Magus Killer, Kiritsugu Emiya understood the twisted worldview of Magi very well.

The long-cherished wish of Magi was to pursue the Root, and to achieve this goal, they would stop at nothing.

Life, to them, was merely a moving reserve of magical energy.