Like Semiramis, Shinji also devised a detailed plan and was waiting for the crucial moment when the airborne garden would strip the Holy Grail from the ley lines. Everything done prior was merely groundwork for this critical juncture and the subsequent wrap-up, aiming to maximize his chances of success.
Of course, there were differences. While Semiramis aimed to securely transfer the Holy Grail to the airborne garden, Shinji wanted to maintain the current state—not returning it to the underground altar, but having it hover above the ground, boldly showcasing the existence of this artificial miracle.
Thus, when Semiramis separated the Greater Holy Grail from the altar and raised it to the surface, Shinji activated his array of spells. These spells, designed by Justeaze, the creator and core of the Greater Holy Grail system who knew it best, were set up by Shinji at various nodes around the castle during his spare time.
The sole purpose of these spells was to strengthen the connection between the Greater Holy Grail and the ley lines, fixing it in place, neither falling back to the altar nor being taken away.
The Greater Holy Grail had been hidden beneath Millennia Castle for sixty years, closely intertwined with the ley lines. For Semiramis to take it away was akin to opposing the entire ley line system of Trifas single-handedly. Even as a demigod-like sorceress who suppressed an era, with the airborne garden as her backup, it was no easy feat—evident from the exceedingly slow ascent of the Greater Holy Grail. Otherwise, with her mastery of space manipulation reaching the realm of magic, she could have transferred the Greater Holy Grail in the blink of an eye, without all this trouble.
The process of transferring the Greater Holy Grail was like a tug-of-war. On one side were Semiramis and the airborne garden, on the other was the ley line system of Trifas. Initially, despite the ley lines' immense power, they were uncoordinated and naturally couldn't match Semiramis, who could concentrate her power. But now, with Shinji's intervention, the ley lines' power was significantly concentrated, making it impossible for Semiramis to budge the Grail—no matter how powerful her EX-Rank Noble Phantasm was, it couldn't surpass the energy source of the Greater Holy Grail.
Hence, this magnificent scene that left everyone in awe unfolded.
Servants, summoned by the Holy Grail and given their roles and vessels, would never mistake the Holy Grail once it appeared.
The Holy Grail is the ultimate prize for all participants in the Holy Grail War. When it appears within reach, their actions are predictable—fierce competition, the most intense struggle.
Though this Holy Grail War has a unique format with two major factions, Red and Black, the essence and conclusion of the war remain unchanged.
Regardless of the process, the Holy Grail War will ultimately yield only one winner or, like the previous three wars, no winner at all.
No matter how many Servants are summoned, the entire Holy Grail system will gradually activate as Servants die, following these specific rules:
After three Servants die, mana begins to fill.
After four Servants die, the mana overflows.
After five Servants die, the Lesser Grail manifests, starting to connect to the outside of the world, and the Greater Holy Grail begins its activation.
After six Servants die, the hole to the outside of the world opens, allowing the Greater Holy Grail to function as a wish-granting device, capable of fulfilling most wishes.
After seven Servants die, the hole fully connects to the Root, achieving the ultimate goal pursued by magi throughout history—reaching the Root. Of course, merely reaching it does not guarantee successful entry, which is beyond the control of the Greater Holy Grail.
The death count of Servants does not distinguish between factions. Once the required number of Servants has died, the Greater Holy Grail will fully activate. At that point, anyone who makes a wish will conclude this Holy Grail War. Servants wishing to remain in the current world will need to re-establish contracts, while those unwilling will dissipate into spirit particles.
Given the fifteen apparent Servants and the actual count of sixteen, even with the Greater Holy Grail fully activated and connected to the Root, nine Servants would remain.
However, the Holy Grail War can only have one winning Master-Servant pair, meaning the maximum number of wishes granted by the Greater Holy Grail is two. Moreover, once the wishes are made, all holes and pathways will close. This means that the remaining nine Servants and an indeterminate number of Masters—who, as long as they have Command Seals, are theoretically still eligible to make a wish even without a Servant—will compete for the two wish slots.
The mechanism of the Greater Holy Grail does not stipulate that only the victor can make a wish. In other words, it's first come, first served. Given this major premise, how could the Masters and Servants of the Red and Black factions possibly wait to decide the factional victor first and then battle among the remaining participants to determine the final winner?
What a joke!
The Holy Grail War is just a process; making a wish through the Holy Grail is the result. When the process to achieve the result is no longer singular, who would care about the so-called structured process?
Not to mention an unverified piece of information—it is said that even if the Greater Holy Grail hasn't reached the level of a wish-granting device, it can be forcibly activated to grant some wishes that don't change the world.
In the original Fate/Apocrypha, the monster formed by Danic and Vlad III attempted to do just that.
Granted, Danic was driven to desperation and had no choice but to take a final gamble, and he had no intention of forcibly activating the Greater Holy Grail earlier. But, firstly, before the final battle began, except for Siegfried, who gave away his dragon heart and whose status was uncertain, no other Servants had died; secondly, Danic had studied the Greater Holy Grail for many years and must have had some confidence in his attempt.
Consequently, the number of Masters and Servants competing for the wish could be even greater. Some righteous Master-Servant pairs might want to follow the proper procedure, but if anyone breaks the rules, others will have to follow suit to win.
This is human nature, and Shinji targeted this very weakness. It's an obvious scheme; even knowing it's a trap, they have no choice but to jump in. Because everyone has an uncompromising wish; otherwise, they wouldn't respond to the summons and participate in the Holy Grail War.
Of course, there are exceptions, such as the Watcher sent by the Counter Force, Artoria. She has no wishes entrusted to the Holy Grail, but she will still join the battle at her Master's command.
The only Master-Servant pair truly indifferent to the Holy Grail are Astolfo and Celenike. Astolfo only wants to enjoy his second life, and Celenike only wants to (cough) Astolfo.
However, the absence of this pair doesn't affect the overall situation; it might even be beneficial. Astolfo himself is an unstable factor—who knows when he might decide to use his Noble Phantasm to attack the Greater Holy Grail, given his "Evaporation of Reason"?
Given this, why not go all the way, find an opportunity to sever the contract between Astolfo and Celenike, transfer the Command Seals to Sieg, and then let the two of them leave Trifas to live their own lives?
With this decision made, Shinji turned around, his figure gradually fading.
Since he had no wish entrusted to the Holy Grail, now was not the time to wade into the chaos. It was better to stay away and watch the show. Hmm, maybe bring along Artoria and Jeanne, watch the chaos unfold, and hunt for the mastermind behind the scenes—wouldn't that be delightful?
Oh, and get some sunflower seeds, peanuts, and mineral water. Too bad the timing is off; there's no free air conditioning and WiFi.
P.S.: How many wishes the Greater Holy Grail can grant is unknown. This is just the information released publicly and hasn't been verified. After all, neither Fate/Stay Night, Fate/Zero, Fate/Apocrypha, nor the first three Holy Grail Wars had a true Master-Servant winner who made a wish.
It wasn't until the FGO timeline that the wish-granting nature of the Grail was confirmed. In the 2004 Fifth Holy Grail War, the previous Chaldea director, the current director who died in the prologue, and the father of Olga Marie, who no one remembers, obtained the Holy Grail with King Solomon and made their wishes.
Spoiler alert!
The previous director's wish was for a large amount of money, which was used to build Chaldea. Solomon's wish was to give up all his powers and become a true human. As a puppet linking humans and gods in life, he longed for true freedom.