Disguise

Disguises are a key plot element in several Final Fantasy titles. Unlike an alternate outfit, a disguise is not under the player's control. Rather, disguises appear frequently in a given story to convey an element of stealth or surprise.

Final Fantasy
Astos disguises himself as a king in the Western Keep to convince the Warriors of Light to obtain a Crown from the Marsh Cave.

Final Fantasy II
Princess Hilda is captured on the Dreadnought. The party frees her and returns her to Altair where they discover that they had instead freed a Lamia Queen disguised as the princess.

Final Fantasy IV
It is mentioned Edward Chris von Muir "disguised himself as a bard to avoid attention". This would imply he was not a bard to begin with, but it is likely that because Damcyan is a country of bards, he has been educated in the ways of a bard, which would explain his skillset.

At an unknown point in time prior to the opening, Cagnazzo killed the King of Baron and assumed his likeness as a disguise. None suspect anything amiss until years later, when "the king" develops a lust for crystals. It is not known who initially discovers Cagnazzo's deception, only that several people suspect as much. He reveals himself when Cecil returns to Baron Castle as a Paladin.

Cagnazzo takes on a subordinate in Baigan, who also disguises himself as a human. His ruse is debunked by Palom and Porom, who note that his acting is as "subtle as a crutch". It is unknown whether Baigan was human or a monster to begin with.

One may bear witness to a dancer in Fabul who appears to be a woman, but throws off a disguise to reveal that he is a man. Similarly, if Cecil as a Dark Knight visits the inn at Mysidia, a dancer will hypnotize him, then turn him into a pig and runs off as an old crone.

Final Fantasy IV: The After Years
The Eblan Four are masters of disguise, and so exemplify the essence of ancient ninja. Each uses the art of disguise to infiltrate his or her assigned mission field. Gekkou masquerades as a monk in Fabul; Zangetsu poses as a dwarf in the underworld; Izayoi becomes a guard trainee in Troia Castle; and Tsukinowa goes undercover as an apprentice mage in Mysidia.

Kain Highwind appears as the Hooded Man and rescues Ceodore Harvey near Mysidia after the Red Wings airship crashes.

Final Fantasy V
Faris disguises herself as a man to make her life as a pirate more comfortable.

Being a dark warlock born an enchanted tree in the Great Forest of Moore, Exdeath can disguise himself as all manner of wood, once even hiding as a splinter in Krile's hand. When the party visits the Great Sage Ghido, Exdeath separates from Krile to return to his human form and spar with Ghido.

Exdeath's Demons of the Rift also disguise themselves in varied attempts to trap the heroes. Halicarnassus is but an example of this, posing as a damsel-in-distress prior to facing off with the party.

The party can wear a moogle costume to trick a moogle into getting a chest in the Moogle Village.

Final Fantasy VI
Locke Cole can wear various disguises when he infiltrates the occupied South Figaro. Due to a glitch, he can even wear the disguises as an "alternate outfit" for the rest of the game.

Celes impersonates the opera singer Maria, the object of Setzer's desire, at the emcee's request to prevent abduction of the latter. Though Ultros throws a wrench into the party's plan to save Maria, Setzer still manages to nab Celes in her stead, but Celes turns the tables on him and uses her doppelganger status to enlist his aid. Both Locke amd Setzer marvel at how beautiful she looks.

Edgar changes his appearance and assumes the name Gerad to conceal his identity as king of Figaro to persuade the Crimson Robbers, who were previously detained in the castle's prison, to reveal the secret path to it.

Final Fantasy VII
On the mission to Sector 5, the AVALANCHE crew dons a set of simple disguises to evade train staff. Their plan falls apart when forged ID cards fail an automated security sweep.

During the Wall Market sequence, Cloud Strife disguises himself as a woman to infiltrate Don Corneo's mansion.

By the time the party reaches the Cargo Ship, each has disguised himself/herself as a Shinra soldier. Even Red XIII joins in, attempting to stand on his hind legs near the crow's nest of the ship. Barret wears a sailor suit, where Cloud might comment that he "looks like a bear wearing a marshmallow". The ladies of the party find this amusing, even suggesting that Barret keep the suit for nightwear.

The inhabitants of current day Nibelheim are Shinra staff disguised as townspeople.

In Junon after the Meteor is summoned, Cait Sith disguises himself as a reporter in the conference room and incapacitates Scarlet. If Yuffie was obtained she also disguises herself as a news reporter and rejoins with the group.

Jenova would seem the ultimate master of disguise, as it is able to project any being it wishes to.

Final Fantasy VIII
The party disguises themselves as Galbadian soldiers at Missile Base.

Ultimecia takes on Edea Kramer's identity to take over Galbadia, although this is more of a case of enthrallment than disguise, as Edea was unknown before rising to power by Ultimecia's behest.

Final Fantasy IX
Princess Garnet wears a White Mage robe to disguise herself while attempting to run away from Alexandria Castle. During the same sequence, Tantalus Theater Troupe members, including Zidane pose as knights in the attempt to kidnap Garnet, only to have her flip it into the escape plan.

When the party visits Lindblum for the first time, local actor Lowell Bridges wears a moogle suit to escape his over-excited fans from the set of his new play Moogle Wannabe II.

Zidane Tribal conceals his appearance with a black cloak in the ending. Kuja could also be seen as wearing a disguise, as he conceals his tail to hide his identity as a Genoma.

Final Fantasy X-2
In the opening event, Leblanc uses the Songstress dressphere to disguise herself as Yuna. Meanwhile, Yuna wears a moogle costume as a disguise during Leblanc's concert in Luca.

Final Fantasy XII
Though the element of disguise is almost nonexistent, assumed identity plays a major role in the plot.

Gabranth (given name Noah fon Ronsenburg) is an identical twin with Basch fon Ronsenburg, and was able to impersonate the latter during negotiations at Nalbina Fortress while Basch and his detachment tried to reach King Raminas to stop them. This sets Gabranth up to frame Basch for Raminas's assassination.

It is unknown how Princess Ashe staged her own death, but she also poses as Dalmascan resistance fighter "Amalia", who joins the party in the Garamsythe Waterway and is captured after the battle with Firemane.

A radio onboard the Strahl can record the voice of any who so much as come near the ship, whereupon the speaker can impersonate any captured voice via synthesis.

"Balthier" and "Reddas" are the assumed identities of two Judges that renounced their station amid the Archadian Empire's corruption.

Final Fantasy XIII
Barthandelus is fal'Cie who is a a master of illusions. He governs Cocoon under the guise of Galenth Dysley, and once masquerades as Serah Farron when he travels to Oerba to meet with Lightning's party. Lightning and Snow see through his disguise as the "Serah" they meet acts nothing like the Serah they know.

Final Fantasy XIV
Yda Hext of Ala Mhigo died in a war before the beginning of the events in Final Fantasy XIV. Her little sister Lyse Hext disguises as Yda and continues fighting to liberate her homeland and working with the Scions of the Seventh Dawn where Yda was a member of.

Final Fantasy XV
Ardyn Izunia can create illusions and make himself and others appear as someone else. His entire appearance could be seen as a disguise, as black markings at times appear on his face, showing how he is corrupted by Starscourge, something he conceals unless he deliberately wants to show others his true nature.

In Final Fantasy XV: Episode Ignis, Ardyn appears in the guise of Gladiolus Amicitia, but Ravus Nox Fleuret sees through the ruse when "Gladiolus" ignores the wounded Noctis and Ignis and walks straight up to him instead, something the real Gladiolus would never do.

Ardyn switches places with Prompto Argentum on the train through Niflheim. In Chapter 11, Prompto takes up the guest party spot, and says lines he has never uttered before, and the player never needs to rescue him from Danger status. He moves slightly differently than before, the way he stands up and his swagger walk being the most noticeable. Similarly, "Ardyn's" statements when Noctis pursues him on the train have him behaving in a way unlike how Ardyn normally acts, such as claiming that he wouldn't come up with something like generating a snow cloud even if he wished, as well as panicking when Noctis pursues him in anger and wondering what Noctis means it being "all [Ardyn's] fault". When Noctis catches up with the duo atop the train, he finds "Ardyn" holding "Prompto" at gunpoint with Prompto's gun. When he attacks "Ardyn", who falls off the train, it is revealed this person was Prompto and the real Ardyn knocks Noctis out to make his escape.

In Zegnautus Keep, Ardyn disguised as Noctis approaches the wounded Ravus, who is delighted to see "his king" and tries to bequeath the Sword of the Father to him. "Noctis" manifests the Sword of the Father, as Ardyn already had it, and kills Ravus with it.

Final Fantasy Tactics
A Glabados Devout lookalike of Cidolfus Orlandeau dresses as him and is willfully slain by Delita Heiral to fake Orlandeau's death.

Final Fantasy Type-0
During the Operation MA Demolition, the Class Zero cadets disguise themselves as Imperial soldiers.

When Machina Kunagiri becomes a White Tiger l'Cie, he puts on a mask and outfit similar to his predecessor Qun'mi Tru'e, and goes by the name "Incognitus".

Final Fantasy Adventure
Unbeknownst to Sumo, Julius disguises himself as a common Red Mage and gets himself lost in the Cave of Marsh, waiting for an adventurer to help him defeat the Twinhead Hydra at its core. As Sumo next escorts Fuji to meet with Bogard, Julius waits to abduct her knowing full well that she is the key to the power of Mana. Sumo's quest then becomes to rescue Fuji for a large part of the story.