Ionioi Hetairoi

"Their bodies may return to ash, but their spirits still hear my call! These men are my legendary heroes – my loyal followers! They’re my true friends - breaking the rules of space and time to fight once more at my side!"

- Rider

Ionioi Hetairoi: Army of the King ("" in n) is the ultimate Noble Phantasm of Rider. It is a Reality Marble that embodies Alexander the Great's dreams and philosophies as a king and the bond formed with his subjects, his life sublimated as as Noble Phantasm. Like how Saber's Excalibur can be called the physical actualization of her ideals as a king, Ionioi Hetairoi is the actualization of Alexander's commanding abilities and his kingship. It is an irregular Reality Marble compared to those used by others. Normally only a magus or something beyond normal reality like Demons are capable of materializing the environment inside their minds, and as Alexander is neither, reproducing it alone is impossible for him. It comes about through the combined efforts of his personal guard, who vowed allegiance to him after many victories and defeats, even after death and becoming Heroic Spirits as well. They can recreate the land in which they once marched and shared many joys and sorrows, as it is imprinted upon the heart of each soldier, allowing them to bring about a sand-filled expanse roaring with hot and dry desert winds under the scorching sun and cloudless, clear skies without anything to obscure the everlasting horizon.

Once fully materialized, the heavily armed cavalry of soldiers slowly appears as mirage-like images and completely manifests as a diverse fighting force with the fierceness of a true army. The entire fighting force is fully composed of a peerless array of famed and legendary warriors only heard reverently in legends, all of whom personally fought with Alexander on the battlefield. They swept across continents during life, and no matter what they faced, enemy or fortress, it was powerless before them. As a leader who only desired to become stronger and more magnificent, live more fully, and become a man more real than any other, he left upon them an impression of never-ending loyalty that not even death can conquer. They are able to break the rules of space and time to fight once more at the side of their king, and like him, they wager everything that they are on the king's dream. They are his greatest treasure within treasures that make up his right to rule, and they are his true friends. They display the violence that reveals Alexander's method of tyrannical kingship without restraint, and he only takes pride in it. Their thunderous cries and their spirit could split oceans, and even someone as proud and haughty as Gilgamesh is left silent upon seeing such a radiant army.

The members that make up his army include the Lord of War, the Maharaorajah, the founders of many dynasties, and even his horse, the legendary charger (ブケファラス), a sleek and powerful black steed who has become a Heroic Spirit along with the rest of Alexander's warriors and would be just as impressive as any of them if he were a human. The Fate/Zero Drama CD introduced an illustration with a number of unique designs that were also given specific detail upon Ionioi Hetairoi's deployment in the anime adaptation. The nature of the Reality Marble is not something like simply summoning the soldiers as familiars, but rather the EX rank of the ability comes from the fact that it is the consecutive summoning of multiple independent Servants.

They are all Master-less Servants, but they each have the rank E- equivalent of the "Independent Action" skill, meaning that they cannot leave the Reality Marble under normal circumstances and can only remain materialized for "thirty turns." They lack Skills and Class designations due to being summoned through Rider's ability, making it unnecessary to assign them anything based on the rules of the Holy Grail War, and, due to limit of Rider's abilities, their Noble Phantasms cannot be materialized. There are also some Heroic Spirits that are stronger than the summoner himself, as while his deeds were great, it is not a testament of his personal martial prowess. The army numbers in the tens of thousand, allowing them to easily overwhelm the less than one hundred Assassins like they are insignificant without the bulk of them having to act.

The generated land is Alexander's preferred battlefield due to the wide plains allowing him to best display his numerical superiority. He generally leads the army at the front of the vanguard while atop Bucephalus, but he can also freely use Via Expugnatio within the confines of the Reality Marble if he wishes. Their battlefield, sublimed into eternity, can be actualized anywhere, and if he were to again set forth in tyranny, all of his servants would hasten to him no matter his location. He believes that equipped with weapons from the Gate of Babylon, it would become the most powerful army capable of easily conquering the modern world. Tens of thousands of soldiers paired up with unlimited Noble Phantasms would produce a most ideal result. Its strength is great enough that simply thinking about it can cause even Saber to tremble, and she is uncertain of her victory against it even after going all out with Excalibur. Rider is prepared to face any threat that they may come against them, whether it is an Anti-Unit attack directed at destroying only him at the head of the army, or something large like an Anti-Army or Anti-Fortress attack, and overcome it so that they can easily trample the enemy before they can launch the next attack. He can freely organize the positions of those that enter Ionioi Hetairoi, grouping them to keep allies safe and align enemies directly before his army. He can also choose where to deposit them after releasing it, though only within one hundred meters.

It is within the boundaries of ordinary space to summon a single soldier into the normal world without them being crushed by its corrective impulses. This allows Rider to summon Bucephalus without needing to deploy the Reality Marble, and if he needs to communicate with the outside after it has been deployed, he can send a single soldier, (ミトレネス), outside of it briefly to receive and relay messages. It takes a great deal of energy to maintain it, and like most Reality Marbles, it can only be utilized for a few minutes at a time. Both the activation cost and the summoning of the Servants are taxing, but he claims that it wouldn't cost as much if most of the army isn't brought out. Due to Waver Velvet being unable to provide enough energy for it, he has to use his own reserves to maintain it. Using it two nights in a row brings him to the point where he is forced to take spiritual form to conserve as much energy as possible, and even after receiving boosts in energy from three Command Spells, he still can only use it one more time. Once activated, it is maintained by the collective prana of the entire army, which means that it will not remain stable if a large portion of the army is destroyed in a single attack.