Laruto

Laruto is the former Sage of Earth in The Wind Waker. She is a Zora, the only one of her race to appear in The Wind Waker. She was born in Zora's Domain, before Hyrule flooded. She was killed by Ganon after he broke the seal of the sages. After her death, her spirit remained in the Earth Temple until she was replaced by her descendant Medli.

Background and Purpose
Laruto had served as the Sage of Earth, praying that the the power to repel evil would remain within the Master Sword. After Ganondorf killed her, her spirit remained in the Earth Temple, waiting for a successor. After a long time, a new hero visits the temple and Laruto appears before him, requesting that he find the new sage. Laruto gives Link a couple of hints regarding how he can recognize the new sage and teaches him the Earth God's Lyric, the song that will awaken the new sage.

Link leaves the temple and finds the new sage: Medli. He plays the Earth God's Lyric for her, causing her to lose consciousness. In her "dream" she is visited by Laruto, and the two play the Earth God's Lyric together. When Medli wakes up, she asks Link to bring her to the Earth Temple.

Laruto's last appearance is when Link defeats Jalhalla. When Medli plays the Earth God's Lyric, Laruto appears next to her and plays along. She disappears again when the Master Sword has regained (part of) its power, finally freeing her from her obligations.

Trivia

 * The name Laruto seems to be reference to the name Ruto, which belonged to the Zora princess in Ocarina of Time, who was also a sage.
 * Laruto is one of the people Link cannot get a pictograph of. To get her figurine, he must obtain her Legendary Pictograph from Lenzo.