Fairy

Fairies are a race of creatures that have appeared in every The Legend of Zelda game to date, excluding Spirit Tracks. Most fairies are small creatures with healing powers, and they usually fly by means of delicate, insect-like wings. Their appearances vary from game to game: in some games, such as Ocarina of Time, they resemble small orbs of light with four wings, while in others they take the form of tiny winged human females. In several games, a group of fairies can be found in Fairy Fountains scattered throughout the land of Hyrule ready to either heal Link or be stored in an empty bottle for later use.

Role in games
Fairies usually have one of two roles in Zelda games. First, using their healing powers, they can restore some of Link's health when he is wounded. These fairies can usually be caught in Empty Bottles for later use. If Link falls in battle while carrying such a bottled fairy, it will automatically come out to revive him. These fairies usually stay in Fairy Fountains and wait for weary travelers, although they can also sometimes be found throughout the game world. In some games, such as Link's Awakening, Anti-Fairies and Sparks can be turned into fairies by using the boomerang.

The second role held by Zelda fairies is that of a traveling companion. In several games, beginning with Ocarina of Time, Link has been accompanied on his travels by fairy companions. Although in many cases they are used to facilitate gameplay (allowing targeting, for example), they also provide invaluable advice on what to do next or how to defeat certain enemies. In Ocarina of Time, every Kokiri is partnered with such a guardian fairy. The fact that Link is the only Kokiri without a fairy (before Navi is assigned as his partner by the Great Deku Tree) is a major plot point and foreshadows the revelation that he is actually a Hylian child.

Great Fairies
Some games also feature beings called Great Fairies. Great Fairies are much larger than regular fairies, being the size of a full grown Hylian (or even larger), and they almost invariably resemble the winged women form of fairies (the only exception to this rule is the case of the Great Fairies in Ocarina of Time and Majora's Mask, who resemble beautiful women and can fly, but have no visible wings).

Great Fairies reside is specialized Fairy Fountains known as Great Fairy Fountains. They also help Link, often by providing him with special power-ups or increased carrying capacity. The precise connection between fairies and Great Fairies is not clear, although in Majora's Mask, the Great Fairies can be resurrected by reuniting certain stray fairies from throughout Termina. These stray fairies are dissimilar to the other fairies from the same game, such as Tatl and Tael. The unusual pink fairies from The Legend of Zelda: Oracle of Ages seem to be based on these stray fairies.

Link's fairy companions

 * In Ocarina of Time, Link is assisted by Navi, who helps keep him on track by reminding him where to go. She also helps him target objects and enemies, and can provide information about enemies.
 * In Majora's Mask, Navi is replaced by Tatl, a new fairy who serves the same purpose as his previous fairy.
 * In the Wii version of Twilight Princess, a fairy resembling Navi is used as an on-screen cursor whenever the Wii Remote is pointed towards the sensor bar.
 * In Phantom Hourglass, Link obtains a companion fairy which he did not have in The Wind Waker, her name is Ciela. Two other fairies (Leaf and Neri) also come to his aid later on. Each of the three fairies represents one of the goddesses (courage, power, wisdom) and give Link a unique power when equipped.
 * In A Link to the Past comic, Epheremelda is fairy that appears after Link retrieves the Master Sword in the Lost Woods and after he fights Agahnim for the first time. Link saves her from a group of thugs who want to abuse her magic.
 * In the manga for Link's Awakening, Link was accompanied by a fairy called Felicia. After the Wind Fish awakens, she disappears, along with the rest of the island.
 * In The Legend of Zelda TV show, Link is accompanied by Spryte, a fairy princess.
 * In The Legend of Zelda comic book series, Link's companion fairy is Miff.

Oddly, all of the canon companions are in the ball of light form and all of the non-canon ones are in the human form.

Fairy Spirits
There is evidence throughout the series that the ball of light form is another species called spirits. In Ocarina of Time, the faeries are referred to as Fairy Spirits in the potion shop. The fairies in Oracle of Seasons are the human form, but the Season Spirits look identical to colored "light" fairies. In Four Swords Adventures, the maidens can turn into a form the resembles light fairies. In The Wind Waker, the fairies are in their original human form, however in Phantom Hourglass, which has the same art style, the only fairies that appear are the Spirits of the Ocean King.