Faldeus Dioland (ファルデウス・ディオランド, Farudeusu Diorando?) is the "True" Master of True Assassin in the True and False Holy Grail Wars of Fate/strange Fake. He is a high-level operative of the organization in charge of setting the foundations of the Holy Grail Wars in Snowfield.
Faldeus is a magus responsible for starting the False Holy Grail War, and despite seeming to be barely past his mid-twenties, displays knowledge of the events seventy years prior as if having had experienced them personally. He is part of a "certain American organization" that answers to the American government. Rather than being an organization of magi, it instead only has some magi as members. He went undercover within the Mage's Association with the eventual purpose of spreading news of the ritual and a warning to the Association's magi. He also learned much about the organization under the tutelage of Rohngall while only revealing his name to the magus. He earned enough of a reputation to be recognized on sight by the Wolf's creator.
While posing as the apprentice of Rohngall, Faldeus takes on a meek and questioning personality who will not even refer to his master by name. Upon dropping the identity, he takes on an icy glare, emotionless face, and ruthless personality. He maintains an upbeat personality even when ordering people to be killed, and faces threats without seeming menacing or threatening. He makes light of those he kills, mocking them during and after death. He claims that he likes to talk, but the possibility of leaking information means that he can only have candid conversations with corpses.
Faldeus shows to think highly of his nation, telling Rohngall to not underestimate a young nation. This patriotic side of him is shown again when True Assassin asks his master where his conviction lies where Faldeus replies that he dedicates all of his magic to the United States of America and is willing to sacrifice civilians if it is for the sake of his country; despite his willingness, to sacrifice lives, Faldeus seems to care for the lives of his own soldiers as he gave them specific instructions so they won't be caught during the clash between Enkidu and Gilgamesh.
Rohngall and Faldeus arrive in Snowfield on orders from the Mage's Association to investigate the possibility of the Holy Grail War ritual being performed there due to the findings of Lord El-Melloi II. Rohngall disparages his apprentice for not taking the possible threat seriously enough even though he displays proper knowledge of the ritual from his readings. They speak of the validity of the rumors and possibility of the land itself having been crafted solely for the sake of reproducing the ritual. Rohngall comments that the land's history is too young for a path to the Root to be reached without it besmirching the honor of magi. Faldeus eventually reveals himself upon claiming the existence of only six classes, leading to Rohngall lecturing him about the seven classes before Faldeus completely drops his ruse. Addressing his "master" by his name for the first time, he begins to explain the differences in the False Holy Grail War, such as the lack of the Saber class, due to its incomplete nature.
Though he has a young appearance, he speaks of the process of copying the Third Holy Grail War like he was part of it, and tells Rohngall that it is not prudent to make light of a young nation as he did previously. Faldeus is completely calm despite his former master treating him as an enemy and preparing his attack. He explains certain aspects like that his organization is one that simply employs magi rather than a group of magi copying the ritual. While Rohngall prepares his attack, he claims that Faldeus is underestimating him, which is followed by Faldeus commenting about "giving his all" and a slight of hand with a cigar. Rather than having been preparing magecraft, it was instead a signal for his Thorn shooters to attack.
After Rohngall is shot dozens of times, his subordinates show themselves as he taunts his "master's" supposed corpse. He explains the nature of Rohngall's puppet body to the unknowing soldiers and his reason for gloating and explaining the nature of the war to him. Having declared his warning to the magi, it marks the beginning of the Holy Grail War. The Kuruoka family expects it, while the Police Chief sees it as a hindrance. He later appears to the magus who created the Wolf that summoned False Lancer, as to remove a possible hindrance from the ritual. Keeping the Association and Church at bay without having wandering magi without Command Spells making enemies of the militia is a troublesome enough task for them, so he slits the magus' throat.
While the magus slowly dies, he explain that there is no need to answer questions or let the magus live, so he tells the magus to simply listen to him before ordering for him to be shot. Speaking with the corpse, he is concerned about Rider and notes the magus' idea of trying to circumvent the rules to summon a god was astonishing. Noting Lancer's summoning, it is actually surprising to him, but it brings a pleasant smile to his face. He claims that Lancer may not be far off from the magus' sought after power of a god had he been a Berserker. Though Lancer shouldn't have been summoned under the system, he does not have much faith in it given the various anomalies occurring.
Faldeus receives a call from a general informing him that a presidential candidate likely to win died, along with 35 influential people in finance, mass media, and major lobbies, all from accidents and natural causes in the afternoon of the previous day. The general asks Faldeus to contact him if he finds any connection to the Snowfield ritual. After comparing the times and places of deaths on a map, Faldeus found a pattern centered on Galvarosso Scladio’s headquarters and linked in order of proximity, but Faldeus is yet unable to confirm if Galvarosso himself has been killed and reasoned that if he was the Scladio mages would conceal the fact for some time. Faldeus then hears a weather report about a massive hurricane headed toward Snowfield, which makes him question about who and what faction is responsible, and what they are trying to summon.
Faldeus has enough ability as a magus to work under Rohngall as an apprentice, and Rohngall believes that Faldeus did nothing to hide his true abilities. Despite Rohngall believing himself to know all of Faldeus' capabilities, he cannot overcome his experience giving him a great sense of unease from facing Faldeus. Faldeus does not attempt to actually fight as a magus, instead relying on armed guards to kill targets on command. With a signal, over a dozen shooters are able to easily destroy any target from various locations. His subordinates wear black balaclava and camouflage gear, and they carry assault rifles equipped with silencers, each engraved with a different design. They are very respectable to him, and it is hard to tell their races or emotional states. Most are not familiar with magi, so they are unfamiliar with things like Rohngall's puppet body. Rather than use a ritual magecraft knife to kill, he simply uses a Swiss Army Knife that can be found in any store.