Laruto

Laruto (ラルト) is a character from The Legend of Zelda: The Wind Waker. She is a Zora and the the former Sage of Earth, one of the sages responsible of maintaining the Master Sword's ability to cast down evil. While praying in the Earth Temple, she was assassinated by Jalhalla, King of the Poes, in order to prevent the Master Sword from presenting a challenge for the returning Ganondorf.

Biography
Laruto was born in Zora's Domain and eventually, she became the Sage of Earth just like Fado was the Sage of Wind, dedicating her life to ensuring that the Master Sword would always have the power to banish evil and that the legendary Hero could use it should he return. However, the great evil that was sealed away at the end of the Imprisoning War, Ganondorf, somehow managed to escape from his prison and since a new hero did not appear to challenge him, he began establishing dominion over Hyrule once more. However, Ganondorf had a lingering suspicion that a hero could eventually appear and challenge him; to this end, he ordered Jalhalla to travel to the Earth Temple and assassinate Laturo. Jalhalla and his minions conquered the temple and successfully killed Laruto. However, the spirit of Laruto remained behind to ensure that a successor to the line of Earth Sages could be found.

Eventually, Link comes to the Earth Temple and encounters the spirit of Laruto. She tells him about her situation, and she asks Link to find her successor. To aid him in identifying this new Earth Sage, she teaches him the "Earth God's Lyric", a mysterious song that has the power to awaken the Earth Sage within the new successor. Link eventually finds that the Rito Medli is the true successor, and together, they travel to the Earth Temple. Laruto helps Medli realize who she is, and asks of Link and Medli to defeat Jalhalla and cleanse the prayer chamber of its evil presence. The two work together to brave the trials of the Earth Temple, and Link eventually finds and defeats Jalhalla.

The evil power now cleansed, Link and Medli play the "Earth God's Lyric" together, restoring the sharp edge of the Master Sword's blade. Laruto also appears again to play the song together with Link and Medli. Her purpose now fulfilled, she departs the world of the living.

Theory
There is a possibility that Laruto is the descendant of Princess Ruto, the Sage of Water during the Imprisoning War. Considering the similarity between their names and statuses of being Zora sages. This theory seems much more likely, especially since an image of Ruto is seen in the stained glass windows of Hyrule Castle, indicating she was still a legendary figure when Laruto was alive.