She can first be seen in the Kokiri Forest when Link is a youth. She stands on a platform that can only be accessed by crossing some ladders. If Link manages to cross them, she says that he has become a "real man".
She appears again in the Lost Woods when Link is an adult. After Link trades the Odd Mushroom for the Odd Potion in Kakariko Village, he is supposed to bring it back to Grog in the forest. However, he is nowhere to be seen, and Fado stands where he used to sit. She tells Link that he has become lost in the woods and become a Stalfos. She then asks for Link to return the potion to her, as it is made of forest materials. She gives him the Poacher's Saw in return.
Early screen shots of a kokiri who is presumably Fado. It shows her wearing a non Kokiri outfit and is sitting on a ledge presumed to be the ledge above the Kokiri Shop. It is possible this was the clothes style for all Kokiri early on in the game, or that Fado was intended to play a bigger role in the story.
Fado's name comes from "Fa" and "Do", two syllables in the Solfège.