Minish Cap Story
In Minish Cap, Vaati was originally one of the Minish race. He was fascinated by the evil of the heart of men, and his master was Ezlo. When Ezlo made a hat that granted wishes, Vaati stole it and turned Ezlo into the hat form he is seen in throughout the game. With this, he turns himself into a powerful Wind Mage then seeks out to become the most powerful sorcerer ever seen. In the end, Vaati transforms himself into a demon in order to try and defeat Link and take the rest of the light force. Link stops him however, and seals him with the Four Sword.
Vaati claims he does all of this for a couple of reasons. First, he felt as though he had to surpass his master Ezlo, because he was a novice and it was very hard. Second, after studying the humans and the great people, he realized that great people did bad things. He thought that if he was bad, life would be much easier for him, so he left and went to the human world.
 Four Swords Story
In Four Swords, Vaati's legend from Minish Cap lives on. He is sealed away by the Four Sword and the maidens whom he captured before. During the beginning of the game, though, the seal is broken and Vaati is unleashed. He then becomes the main antagonist once again, and you must fight to save the Princess and Hyrule. After you seal Vaati once again, Hyrule is at peace for a time. However, this changes when Ganon stole the Dark Mirror to create Shadow Link, who stole the shrine maidens and tricked Link into unleashing Vaati and the Four Sword. You must once again destroy Vaati as well as Ganon in Four Swords Adventures.
 Human Form
 Minish Form
 Vaati Reborn
 God Form
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