Navi

Navi (ナビィ, Nabi) is Link's fairy companion from Ocarina of Time. Her name is thought to be short for Navigation. Since Link is not a real Kokiri and does not have a fairy of his own, she is summoned by the Great Deku Tree to accompany Link on his quest to save Hyrule. Navi is also one of the few characters with any voice-acting in the series, and the only other character (aside from Link and Beedle in The Wind Waker) who uses English words.

The precise relationship between her and Link is a matter of contention, since it is left ambiguous by Nintendo - the only time she speaks during the game (with the exception of the "Hey" and "Listen" sound effects) is during the introductory sequence and during the Temple of Time sequence. Other than that, she provides Link with hints on where and what to do next. At the end of the game, when Link returns to his original time, she leaves him and flies away for undisclosed reasons. She was last seen flying into the large window behind the Pedestal of Time. This is interesting since in Twilight Princess, it is concluded that the dungeon entrance to the Temple of Time is the exact same window from Ocarina of Time.

It is widely speculated that the "friend with whom he parted ways when he finally fulfilled his heroic destiny", mentioned in the introductory sequence to Majora's Mask, is Navi. This is made all the more probable given the "fairy flying" sound-effect that is played after the text disappears off the screen, but before the Lost Woods scene begins. She has not been seen in any other Zelda games other than the Wii version of Twilight Princess, where her "blue fairy" design is used to indicate the pointer of the Wii Remote when it is not being used for other functions, like aiming the bow.

In gaming terms, her primary purpose is to function as a focusing target, indicated by her position which object/enemy will be locked on to if the Z-trigger is depressed, as well as dispense hints to Link. She glows yellow to indicate when she is targeting an enemy, blue when you can talk to someone from a distance, and green when she is targeting something of interest.

In Super Smash Bros. Brawl, Navi or her "blue fairy" design is seen flying next to Link in front of a forest holding the Pedestal of Time. The scene is named "Link draws the Master Sword". Link pulls out the Master Sword from its Pedestal, although not in the same place as in the real Zelda games. However, after being seen before Link pulls out the Master Sword, Navi (or her design) is not seen afterward at all in Brawl.

Reception
Navi is one of the more criticized The Legend of Zelda series characters. Some gamers become annoyed with her frequent "Hey!" and "Listen!" sound effects.

Trivia

 * Navi is one of the few characters in the Zelda world to break the fourth wall. In Ocarina of Time, if a fish weighing 20 lbs or more is caught at the Fishing Hole, Navi will exclaim "This fish is so big it doesn't even fit on the screen!"
 * Ciela from Phantom Hourglass uses two of the same voice clips as Navi (her "Hey!" and "Look!" clips).