Fado (Ocarina of Time)

Fado is the blonde Kokiri girl standing at the end of the bridges leading from Saria's house in Ocarina of Time. In Link's younger years, all she does is stand there, and when talked to, teaches Link how to look around and warns about the Lost Woods. When Link talks with her while wearing a mask, she says different things than the other Kokiri and usually mentions Mido. On a previous version of the official Zelda website, the caption under a screenshot of her stated that the game designers gave her the name "Fado" during development, though it was never mentioned in the game itself.

When Link returns seven years later, Fado can no longer be found in the village and can only be seen during the Biggoron's Sword sidequest. When Link returns to give the medicine to Cojiro's owner, Fado will be there instead of him. She'll demand Link gives the medicine to her, since it's made of forest mushrooms. In return, she'll give Link the saw the other guy apparently left. Fado mentions that all who enter the Lost Woods become Stalfos and wonders if Link will turn in one too.

Development
Fado is a bit of a strange character. She has her own model (which is unusual for any character that's not a Hylian or has an important role), different lines from the other Kokiri and she mysteriously disappears later on, but she doesn't seem to mean anything for the story at all (aside from acquiring Biggoron's Sword).

More importantly, she appears in some of the early Zelda 64 screenshots and is indicated to be created at about the same time as Saria. On those screenshots, Fado appears to be sitting on the roof of the shop in the Kokiri Forest, which in the released version is occupied by the common model Kokiri girl. She also has her own outfit in those screenshots, unlike in the released version, in which she wears the same outfit as the other Kokiri girls.

Sibling Theory
It is speculated that Fado is Mido's sister. The two arguments for this theory are that they have similar names and that Fado tends to talk about him more than any other Kokiri and in a different way.

Trivia

 * Fado's name was later "re-used" for two other characters. The first one was another Kokiri (though a boy) in The Wind Waker. The second one was an Ordonian farmer in Twilight Princess.