"Oh, you're leaving."
Saria is a supporting character in The Legend of Zelda: Ocarina of Time. A childhood friend of Link, she is one of the Kokiri tribe, a group of fairy folk whose traditional beliefs tell that they will die if they leave Kokiri Forest. The beginning of Link's adventure causes a separation between the two early on in the game, and Saria gives him the Fairy Ocarina as a memento. The two can communicate across great distances by playing Saria's Song.
As a Kokiri, Saria is protected by the father of the forest, the Great Deku Tree. His existence keeps the forces of evil at bay in the forest. The Kokiri, being an ageless race, never grow old, keeping their childlike physique through different time periods.
Saria's role in Link's quest is to give help and advice as much as she can; perhaps her friendship is more important than Link initially realizes. It is presumed that Saria's story lives on in the world of Hyrule, since one of the towns in Zelda II: The Adventure of Link is named after her.