Vaati

Vaati is the main villain in The Legend of Zelda: The Minish Cap and the The Legend of Zelda: Four Swords Adventures. Vaati is a Wind Mage, and is seen taking on two main forms, a humanoid and a flying eyeball (much like Ganondorf and Ganon). Vaati is the second most recurring villan in the series, after Ganon.

The Minish Cap
The origin of Vaati is told in the adventures that Link faced with the Minish Cap. Originally of the Minish race, Vaati was fascinated by the evil that could come from the heart of man. When his master, Ezlo, fashioned a powerful cap as a gift for the humans, Vaati stole the cap, and transformed his master, so that he would not stop him. Then, taking human form, Vaati set out to find the means to allow him to become the greatest sorcerer the world had ever seen. Vaati wanted ultimate power, and sought to obtain the mystical light force; a source of limitless magical power contained within Hyrule's princess. When he finally learned of its location he took the princess to Hyrule Castle to complete his plan. There, Vaati managed to steal most of the light force from Princess Zelda, using it to transform himself into a god-like being in order to combat Link. He was defeated and, in a desperate attempt to survive, took the form of the one-eyed creature he is most commonly seen as today. However, despite his newfound power, Vaati was defeated by Link and was later sealed within the reforged Picori Blade, which was subsequently renamed the Four Sword (due to its ability to split its wielder into four separate beings). Alternatively, in the Minish Cap manga, Vaati returns to Hylian, then Minish form, breaks the curse on Ezlo, and the two reconcile and return to the Minish world.

The Four Swords
Released from his prison within the Four Sword, Vaati kidnaps Princess Zelda, forcing Link to go off and search for the princess. After Link rescued Zelda and sealed Vaati within the Four Sword, Hyrule was at peace, until Ganondorf stole the Dark Mirror and created Shadow Link to kidnap Zelda and the Shrine Maidens and trick Link into drawing the Four Sword and releasing Vaati. During Link's adventure to save Hyrule he found out that Vaati is not the real enemy, that Ganondorf created Shadow Link to trick Link into releasing Vaati to distract him So Ganondorf could steal the Trident of Power to transform into Ganon and take over Hyrule.