Earth Temple

The Earth Temple is the fifth dungeon in The Wind Waker and is located beneath Headstone Island. The spooky, foggy temple is covered with thick, gray walls and shadow-themed enemies, such as ReDeads, Red Bubbles, Poes, and Stalfos. Link goes through this dungeon with Medli, who may be controlled via the Command Melody. Link is able to receive the Mirror Shield in this temple after defeating a Stalfos mini-boss. The Boss of this Temple is Jalhalla. After defeating this giant Poe monster, Medli stays there to pray for the Master Sword, allowing it to regain half of its power.

Many statues in the temple portray sun-like or moon-like entities, hinting towards the dungeon's theme of light vs. shadow. The identity of the entities is unknown.

The Earth Sage was Laruto until she was slain by Jalhalla. Medli becomes the next sage after Jalhalla is destroyed.

History
The purpose of the Earth Temple was to keep Ganondorf imprisoned following the events of The Legend of Zelda: Ocarina of Time. The sages of the temple were Zoras prior to Wind Waker, in which the Rito become the race affiliated with the temple.

Trivia

 * The reason Zoras were sages of the Earth Temple was probably due to its close proximity to Lake Hylia.
 * The Earth and Wind Temples cover the elements not already represented by the temples in Ocarina of Time, though they are more analogous to "shadow-" and "spirit-themed" levels in comparison.