To address the greatest element of instability, Shinji devised a special plan.
This plan required Astolfo's power, so he deliberately left the goddess' scepter behind and stayed in the rear to ensure that this reckless knight wouldn't charge ahead and become targeted by powerful Servants.
Shinji remembered clearly that in the original story, Astolfo got beaten badly because of his excessive recklessness on the battlefield. Initially, he relied on Hippogriff's mobility to steal the Red faction's base. Then, believing that his Universal Magic Resistance Book would protect him from magic, he charged straight at the top-tier Servant Semiramis.
Moreover, because using the Hippogriff's true name release consumed a lot of mana, he didn't want to harm Sieg's companion, which meant that his trump card couldn't be used.
As a result, Semiramis broke through the book's defenses with a series of powerful spells, injuring the Hippogriff and causing Astolfo to fall from the sky. After landing, he encountered Mordred, who arrived late to the battlefield full of pent-up rage, and got beaten up by her. If it weren't for Sieg and Frankenstein, whom Shinji had replaced, risking their lives to save him, he would have died from his recklessness. Of course, compared to Sieg's later exploits, these didn't matter much, so not many people paid attention to Astolfo's reckless actions.
But this time, Sieg's two trump cards—one was replaced by Shinji, and the other was still beating on Siegfried's chest—couldn't be ignored. To prevent him from dying too quickly, Shinji had to rein in this wild, irrational horse.
And this rein was to dictate his every move, leaving him no time for recklessness.
Starting with four threes to counter Atalanta's four twos was part of this strategy. Then, under Chiron's telepathic command, he retreated to heal, and after recovering, he was ordered to follow Spartacus—not to prevent Spartacus from going berserk, but to monitor his every move.
Once Spartacus started turning into a monster, the plan would enter its second phase.
This phase couldn't rely solely on Astolfo's observations, given his instability.
To ensure everything went smoothly, Shinji had to be on-site personally, which was why he didn't enter the duel field created by Achilles. Even if most of his Noble Phantasms were rendered useless, he still had one ace up his sleeve. Given the right moment, this ace could frustrate the Greek hero second only to Heracles to death.
However, outside of a confined space, this ace's lethality would be reduced, and his identity might be exposed. So even under Achilles' fierce attacks, Shinji gritted his teeth and held on, waiting for Astolfo to bring Chiron, allowing him to withdraw smoothly while pinning down Achilles, whose instability rivaled Astolfo's.
It's important to note that the two greatest sources of instability in this Holy Grail War were these two Rider-class Servants. Because of these two, the Rider class's reputation suffered, becoming known as a hotspot for traitors, second only to the Lancer's Curse of Bad Luck.
Of course, "traitor" here didn't mean they harbored ill intentions from the start. It was mainly because these heroes were too capricious. They valued their desires over their allegiance to the Red or Black factions. If you understood their personalities, it was easy to predict their actions and limit them.
For instance, persuading Astolfo to stop worrying about mana consumption to save more homunculi.
For instance, sending Chiron to deal with Achilles.
Shinji needed Astolfo for his Rider class mobility, which Achilles also possessed, but to a greater extent.
In other words, Achilles had the power to ruin Shinji's plans and, being known as the fastest hero, could leave whenever he wanted. If he attacked Shinji at a critical moment, everything would be ruined—since he had Andreias Amarantos, he wasn't afraid of non-divine Noble Phantasms, and Shinji couldn't withstand that.
Fortunately, the only ones who could pin him down, besides Shinji himself, who was mysteriously recognized as another Hector, were Chiron, his greatest teacher.
With Chiron around, Achilles couldn't go anywhere because—
"This is your weakness."
When Shinji heard Astolfo's shouts, he was determined to take to the skies even if it meant breaking an arm.
When Achilles decides to abandon the pankration match rules, materializes a javelin to intercept Shinji and prepares to take on multiple opponents.
When an arrow descending from the heavens deflected the javelin, a man clad in leather armor descended from the sky.
When Achilles saw the man's face, that familiar calm expression, and the smile of a long-lost reunion.
Achilles was stunned.
At that moment, Achilles forgot that Shinji was recognized as a worthy rival who had to be defeated.
At that moment, Achilles forgot that he was on a battlefield.
At that moment, Achilles could see only this man.
—This man, he had seen before.
—No, he had spoken with him, received his teachings, shared meals and lodgings with him...
"You—you are..."
To such an Achilles, Chiron spoke in a calm voice the words he had prepared days ago, and he also kicked his dazed, subpar disciple.
Achilles' body flew into the air from the powerful blow.
Chiron then naturally nocked an arrow and shot it with fluid ease.
"...!!"
The instant Achilles realized the arrow was aimed at his heel, every nerve in his body tensed. He twisted his body to its limit, trying to dodge the arrow's trajectory.
—He dodged it.
The arrow didn't hit the vital spot but pierced his side. Despite the intense pain coursing through his body, Achilles paid it no mind. The man standing before him was a far greater concern.
All the mysteries surrounding the Black Archer were resolved; his archery skills being superior to the Red Archer's was only natural, for he was the teacher of many heroes, including Achilles himself.
Achilles pulled out the arrow lodged in his side and tossed it aside, then stood up.
Chiron still held the bow, standing motionless as if waiting for the Rider to speak.
"—Why, are you..."
"Foolish question. In this Holy Grail War, I have manifested in this world as the Black Archer. And you as the Red Rider. We both have our wishes and attachments. That's why we are here, both you and I."
"..."
Achilles lowered his head into silence.
Chiron sighed and naturally took the stance of a teacher instructing his student:
"Honestly, naivety has its limits. This was the one thing you never corrected in life. You are merciless to those you consider enemies, but with companions, or those you trust, you are endlessly lenient. This might be an admirable trait for a hero, but this is the Holy Grail War. There is no room for mercy, even for a hero like you—do you understand? Achilles."
The Black Archer called out to the Red Rider by his true name.
The young man called Achilles nodded with the seriousness of a student receiving a teacher's instruction.
The master and disciple, separated by Shinji's intervention, finally returned to their starting point.