Crafty and charismatic, Cid Aulstyne once only held the reins of the imperial army. In a bid for power, however, the grand marshal used his influence to launch a coup d'etat. He successfully incarcerated the emperor, seizing control of both the Militesi Empire and its affiliated White Peristylium. Since taking over, he has directed the design and development of new armaments, personally helping produce teknology allowing the empire to seize the Crystals of the other nations in Orience. He has already taken his own nation's White Tiger Crystal hostage and begun forcing its l'Cie to do his bidding. Moreover, he has already made clear his designs on the other three Crystals, so it is only a matter of time until he acts on those intentions.
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.
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
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." He rallies his populace to support his cause by saying the Militesi Empire will become Agito and lead Orience to a new future.
Using his newfound power, Cid begins his conquest of invading the other Crystal-States. Cid breaks the Pax Codex by annihilating the Lorican Alliance with the Ultima Bomb, the empire's new weapon of mass destruction. Afterward, he has the nation's Black Tortoise Crystal salvaged from the ruins. Not having the means to deploy the bomb to the nations lying further away, Cid begins the imperial campaign with with airship fleets and magitek armor to obtain the Crystals.
He has 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 has 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.
Cid has the White Tiger Crystal l'Cie deployed to the war to support the Militesi troops. Some are uneasy about this, but Cid states that as long as they hold the Crystal hostage the l'Cie cannot defy him. In an unusual move, the other Crystals of Orience send their l'Cie to try and quell the war, the Vermilion Bird Crystal deploying Lord Zhuyu to face off against the Primus l'Cie of the White Tiger Crystal Nimbus at the battle over Togoreth Stronghold, and the Azure Dragon Crystal sending Queen Andoria to invoke the Fabula Pact in an attempt to enact a ceasefire. Cid finds the Crystals' attempt to hinder him amusing, but the Militesi war effort takes a step back when Class Zero destroys Brionac, the prototype magitek armor developed to deploy the Militesi ultimate weapon, the Ultima Bomb.
The queen is assassinated and the blame placed on Class Zero whose cadets had been given leave in the Militesi capital of Ingram during the ceasefire. Imperial forces ambush them in their hotel but the cadets escape for their lives, the only casualty being the class orderly Aria Luricara who is left behind, badly wounded. The assassination had been orchestrated by Cid and the man who would succeed Andoria to the throne of Concordia. Cid helped the king usurp the queen and the monarchy's matriarchy to exploit his lust for power to gain access to the Azure Dragon Crystal that the new king relinquishes under imperial watch for its supposed safety. With the regicide blamed on the dominion the joint Militesi-Concordian forces begin their campaign to lay waste to Rubrum.
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.
- 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.
- Cid shaking hands with the King of Concordia resembles the event that Adolf Hitler meets Benito Mussolini for the first time on June 13, 1934 in the city of Venice.