Vaati

Vaati is the main antagonist in the Four Swords subseries of The Legend of Zelda games, appearing in The Minish Cap, Four Swords and Four Swords Adventures. Vaati, much like Ganondorf, takes on two main forms; one human-like, the other a monster. In The Minish Cap, Vaati takes on three other forms, one before his human form, one after his first monstrous transformation and one in between.

The Minish Cap
Originally of the Minish race, Vaati was fascinated by the evil that came from the heart of man. His master, Ezlo, fashioned a powerful magical cap as a gift for the humans that could make one's wishes come true. Vaati put the cap on without permission and transformed into a sorcerer. With his new power, he cursed his master, turning him into a living cap to spite him and to express his superiority. Before leaving Ezlo, Vaati revealed his plan to cross into the human world through the portal that opens once a century. Once on the other side, he would try to find the Light Force, a relic said to be the source of unlimited magical power.

Over the course of the game, Vaati continuously seeks its location. To aid in his search, he impersonates King Daltus and orders the soldiers to look for the Light Force. Many of the guards don't believe in the tales of the Light Force,  even suspecting that the king is not the same person, but continue looking for it under the threat of being imprisoned for disobeying the "king". Vaati learns that the location of the Light Force will be revealed if the Four Sword is reforged, and allows Link and Ezlo to continue their quest.

finds it in the most unlikely of places, within Princess Zelda. Vaati manages to extract some of the Light Force from Zelda and transformes into a tall sorcerer form known as Vaati Reborn. Link defeats the form with the power of the Four Sword, and Vaati transforms into a demonic one-eyed black orb known as Vaati Transfigured, but is vanquished again. In his anger, Vaati transforms yet again, into a larger, more powerful version of this form known as Vaati's Wrath, but even this could not defeat Link, who sealed Vaati within the Four Sword. Zelda then proceeded to use the magical cap to restore what Vaati had done, destroying the cap in the process.

Vaati's Five Forms
In the game, Vaati is seen in a total of five forms: a Minish, a human, a demonic sorcerer, a wind mage, and a true demon form. His humanoid demon sorcerer form has an attack pattern that strongly resembles that of a Patra from the original The Legend of Zelda, his wind mage form moves and looks like Wart in Majora's Mask, and his final form resembles the Nightmare's final form from Link's Awakening.

The figurines for Vaati's boss forms are hidden; they cannot be won in the figurine lottery without first defeating Vaati.

Four Swords
The seal on Vaati was apparently weakened over time, and a long time later Vaati managed to break out of his prison within the Four Sword. Vaati kidnapped Princess Zelda, forcing four Links to go off and search for the princess. After traveling over three different lands and the dungeons they contained, Link and his three other selves confronted the wind mage in the Palace of Winds, the seat of Vaati's power. After an arduous battle between the sorcerer and the heroes, Link was able to reseal Vaati into the Four Swords blade.

Vaati has two forms in this game. The first is Vaati possessing a statue of himself, encased in armor, similar to the Vaati's Transformation form from later in The Minish Cap, and the battle is very much like the battle against Cyclok in the later Phantom Hourglass. In the second form, he appears as he does in the opening cutscene.

Four Swords Adventures
After Link had rescued Zelda and sealed Vaati in Four Swords, Hyrule was at peace for a time. This changed when Ganondorf stole the Dark Mirror from the Temple of Darkness. Creating Shadow Link to kidnap Zelda and the Shrine Maidens, Ganondorf tricked Link into releasing the Four Sword, unsealing Vaati in the process.

During his adventure to save Hyrule, Link found out that Vaati was not the real enemy. Instead, Ganondorf had instigated the ordeal with Vaati to distract Link, allowing Ganondorf the time needed to steal the power of the Hylian Shrine Maidens.

Over the course of the adventure, Link rescued the Shrine Maidens and Zelda, and restored his good name upon defeating Shadow Link with Zelda's help. At the final battle, Link and his split selves defeated Vaati, and sealed Ganon within the Four Sword with the help of Zelda and the Shrine Maidens. With this, peace returned to Hyrule, and the Four Sword was laid to rest in its shrine. With this being the last tale in the Four Swords era, Vaati was supposedly finally destroyed in this game. Whether he actually destroyed Vaati, or merely sealed him inside the Dark World, is unknown.

It is unknown whether this Link is the same one from Four Swords or not because a few things have been changed like Link having a Red Shield in Four Swords Adventures and a Blue Shield in Four Swords and the Link in Four Swords sounds like the Link from Majora's Mask and the Link in Four Swords Adventures sounds like the Link from The Wind Waker.

It is not exactly clear what Vaati's desire was in the Four Swords series.

Four Swords (Manga)
In the Four Swords manga adaptation, Vaati mirrors his role from the game. However, when Link first splits into four, the demonic mage first appears as a stone golem. After the golem's defeat, the wispy form of the wind mage escapes to the Tower of Winds. After the four Links are separated, he sends Big Poe to the Temple of Darkness to eliminate Red and Blue. Later on, he takes the guise of Zelda, luring Link's father into his trap, seeing him as a possible way to kill Link. This plan is foiled by the Links and his father who destroy the disguise. At the final battle, Vaati sends the Links into a surreal world which he commands. But he is ultimately defeated by the four Links and Shadow Link.

The Minish Cap (Manga)
Vaati appears in the The Minish Cap manga version of the game, reprising his role as the main antagonist of the story with his background remaining virtually unchanged though there are some heavy differences that occur in the final battle. During his final fight with Link, he assumes a previously unseen form referring to himself as the Great Demon Vaati, in which he adorns new clothes and a helmet. However, he does not utilize this form for long before assuming his reborn form. However, things go awry as he loses control of the light power whilst his body goes through an uncontrollable transformation into a form resembling his Wrath form, as then he is seen begging to be saved from himself, which Link promptly does, using the Holy Sword. Unlike the game, the sword purifies and redeems his being as he shrinks back to his original Minish form, apologizing to everyone for the evil he had committed in his conquest for power.

Trivia

 * The pronunciation of Vaati's name has been disputed among fans. Some examples would be "VAH-tee," "Vat-ty,", "Vat-TUH" or "VAY-Tay." Nintendo has not confirmed a solid pronunciation.
 * Vaati's name is similar to Venti, the Italian word for winds.
 * In The Minish Cap manga, during the final confrontation with Link, Vaati in his first form wears a headpiece that bears slight resemblance to the one Midna wears in her cursed form.
 * Vaati, especially his final demon forms, resembles many things that have appeared in The Legend of Zelda series, namely:
 * The Nightmare's final form from Link's Awakening.
 * Some images around the Spirit Temple in Ocarina of Time.
 * The wanted poster in Ocarina of Time's Shooting Gallery. though no games had shown an entrance of Vaati at this point.