Kaepora Gaebora

Kaepora Gaebora is a recurring character in The Legend of Zelda series. He is a wise old owl that assists Link throughout his adventures. He can rotate his head in the owl-like fashion, as one would expect, but when he does so, his markings resemble another face looking down at Link.

The Legend of Zelda: Ocarina of Time
Kaepora Gaebora assists Link throughout his childhood, and can also be seen when Link is an adult when he learns the "Requiem of Spirit" from Sheik at the Desert Colossus. One of the Gossip Stones in the game says that Kaepora Gaebora is the reincarnation of an Ancient Sage.

According to the book Hyrule Historia, Rauru followed Link's adventures before Link drew the Master Sword as the owl Kaepora Gaebora. Kaepora Gaebora also appears after Link has pulled the sword. Taken literally this means that Kaepora Gaebora can exist independently from Rauru, only possessed by him till a certain time. However, this statement may also merely be a mistake on the part of the writers, intended to mean that Kaepora Gaebora is always a form of Rauru.

The Legend of Zelda: Majora's Mask
The owl, who is unnamed in this game, appears in the Southern Swamp, when Link is traveling to Woodfall by way of a shortcut. The owl teaches Link the "Song of Soaring", an optional song which allows him to warp to activated Owl Statues, which the owl has scattered throughout Termina to aid the one who can change the fate of the land. He appears again in Goron Village, helping Link to find the Lens of Truth, which is essential for obtaining the Goron Mask. The owl is apparently able to retain his memory even after Link resets time to the Dawn of the First Day; he will recognize Link in Goron Village even if time has been looped since their meeting in Woodfall; also, once he has aided Link he will not be seen again at either of the locations he had been waiting at during previous loops. This ability is hinted at when he tells Link "From the first time you play this song, we shall become eternal friends, transcending time and place!", and may also explain why the Owl Statues he placed are able to remain activated even after time has been looped.

The Legend of Zelda: Four Swords Adventures
The four Links are often guided by Kaepora Gaebora. He is the one who wakes them after they are sent away by Vaati. Kaepora Gaebora appears most often at the beginnings of levels.

Theories
Some believe that Kaepora Gaebora is the alternate form of Rauru, the Sage of Light, who also helps Link as one of the Seven Sages in Ocarina of Time. A major reason for this is that a Gossip Stone seen in Ocarina of Time states that Kaepora Gaebora is the reincarnation of an Ancient Sage, and Rauru is implied to have been residing within the Temple of Light for ages, awaiting the time when the Sacred Realm would be opened. However, it is possible that Kaepora Gaebora is not meant to be a specific sage. Another Gossip Stone says, "They say that strange owl, Kaepora Gaebora, may look big and heavy, but its character is rather lighthearted." Saying that Kaepora Gaebora is "lighthearted" could be wordplay meant to imply that he is the Sage of Light, though it could also mean just what it says; that Kaepora Gaebora has a lighthearted personality. Kaepora Gaebora appears to know a lot about Hyrule and its history, and only someone that had been around for ages would seem to know as much about Hyrule as he did; one of the only people known to have been around that long in the game was Rauru himself. Rauru's robes are the same color as Kaepora Gaebora's feathery body, and his facial expressions mirror those of Kaepora Gaebora.

The theory would also explain why Rauru did not appear with the other Sages at the end of Ocarina of Time if he could only exist in the form of Kaepora Gaebora outside the Temple of Light. Kaepora Gaebora appears at the same part of Death Mountain as the part where the sages appear during the ending credits.

It may seem this theory could be refuted by Kaepora Gaebora's statement late in the game that he thought that the tales of the Hero of Time were "merely a legend." However, it is possible that Rauru had been waiting in the Temple of Light for the Hero of Time for so long that he eventually began to believe the prophecy of the Great Cataclysm would never come to pass. Another flaw in this theory's logic would be when Rauru contacts Link telepathically to tell him about Sheik awaiting him in the Temple of Time, if Rauru was in fact Kaepora Gaebora, one would assume that he would have appeared to him in that form.