In this time of darkness, we must unite to bring forth the light of hope! The time has come! Yes, this is the dawn of a new age!
- —Cid's war declaration
While there have been Cid characters who have served as antagonists in Final Fantasy games before (such as Dr. Cid Bunansa from Final Fantasy XII and Cid Raines from Final Fantasy XIII), this is the first Cid to be the main antagonist of a Final Fantasy game.
Imperial Marshal of the Militesi Empire, home of the White Peristylium. Cid is a charismatic leader and excels at currying favor with the public. He rose to a position of power after arranging a coup in which he wrested control of Byakko's political climate and sent the Emperor to be imprisoned for a litany of supposed crimes against the people. He created an ambitious plan to develop new arms for the Empire's use, completely of his own accord. Now he seeks a way to seal the Crystals of the other three nations so that he may use their energies for his own benefit. His desire for power is so strong that he has taken his own nation hostage and now leads it along the path to war. He forces the Byakko l'Cie to follow his orders by exerting mechanical control over the Byakko Crystal itself, and conscripted them to help him in an invasion on the neighboring country of Rubrum.
- —Character Info
High commander of the technologically advanced army of the Militesi Empire, Imperial Marshal Cid became the country's dictator after the mysterious disappearance of the Militesi emperor. After Cid discovered the truth of "everything about Orience is a part of gods' experiment", he resolved to take action for the sake to freeing humanity from the "slavery under the gods and Crystals."
Using his new found power, Cid begins his conquest of invading the other states of Orience with airship fleets and magitek armor to obtain the Crystals. He first begins by having the Militesi fleet to invade the Dominion of Rubrum from all sides while a squad under the l'Cie Qun'mi Tru'e attacks Akademeia and use a crystal jammer Cid had invented to disable the city's defenses. Cid breaks the Pax Codex by having his l'Cie directly attack the city while forcing Chancellor Khalia Chival VI to comply and relinquish the Vermilion Bird Crystal, or the people still in the Peristylium would be slaughtered. A group of cadets who would later be known as Class Zero drive off Qun'mi and her forces as Rubrum fights back in the war that follows.
Having escaped as Rubrum takes control at the end of conflict, Cid has Nimbus take him to the Pandaemonium where Tempus Finis is to begin. There, he faces the Rursan Judge and how he is to become the one to destroy the world. Faced with this revelation, he commits suicide. Though his death does not prevent his body from being utilized by Judge as the l'Cie Arbiter, Cid chooses suicide rather than become the Rursan puppet. As Class Zero fights their way to him, now a vessel of the Judge, Cid proceeds to place them through several trials to deem their worth.
As they finally face him, Cid proceeds to utterly belittle them for being unworthy to become Agito upon completing his transformation into the l'Cie Arbiter, killing Shinryu Celestia before beating the twelve students to within an inch of their lives. However, the spirits of Machina Kunagiri and Rem Tokimiya manage to give each member of Class Zero the strength to continue and release the Phantoma from the l'Cie Arbiter's body and absorb it at the cost of their lives. This leads to the l'Cie Arbiter's certain defeat.
- Main article: Rursan Arbiter
Cid is fought as the final boss in the form of the Rursan Arbiter.
Cid is voiced by Shuichiro Moriyama in the Japanese version and by Steven Jay Blum in the English version.
Cid is a recurring name in the Final Fantasy series.The word Cid derives from the Old Spanish loanword 'Çid', which comes from the dialectal Arabic word سيد sîdi or sayyid, which means "Lord" or "Master".
His surname could come from the combination of "old" and "Stein", the German word for a rock.
- Cid's rise to power through overthrowing the current ruler, his standing as general in his nation's military, and his actions of world domination upon being at the seat of his nation's highest position draws similarity to the rise of European militant conquerors, most notably to that of Napoleon Bonaparte and Adolf Hitler.
- Final Fantasy Type-0 has many allusions to World War II. The scene where Cid Aulstyne gives a rallying speech to his troops before their invasion of Orience resembles Adolf Hitler's infamous yearly rallies given on the anniversary of him coming to power, and to his most notable of speeches made: his "Lebensraum" declaration and his war declaration on the United States.
- Cid's brandishing of a katana draws its reference from the uniforms and standards of Japanese military commanders during WWII, as the carrying of katanas signified the loose appropriations of the more dominant aspects of Bushido and Japanese patriotism in the Empire of Japan, despite having relinquished many aspects of tradition in the Meiji era and having adopted modern weapons such as guns and rifles.