Spirit of Earth

The Spirit of Earth(S.O.E.) is one of the Five Grand Elemental Spirits.

About
The Spirit of Earth is one of five powerful elemental spirits known as the Grand Elemental Spirits(Godaiseirei), of the Patch Tribe. They are derived from the Great Spirit itself, and like it, constitute a collective of souls. They can be controlled by their respective Elemental Warrior, or a shaman of extraordinary power (like Asakura Hao). The power of the Godaiseirei is unmatched by any other spirit, except for maybe the Great Spirit itself.

After Asakura Hao stole the Spirit of Fire it was hidden, by the Patch Tribe to avoid any other of the Grand Elemental Spirits to be stolen, within the depths of hell and guarded by Enma Daioh, the greatest of the four Kings of Hell.

According to Pascal Avaf, the Spirit of Earth gives life to plants and creates metal. Also according to the recent Kang Zeng Bang Data the Spirit of Earth has the same abilities as the Spirit of Fire to become stronger, by consuming souls.

Anime/Manga Difference
The Spirit of earth does not appear in the anime,But the Spirit of Fire is implied to have been able transform into the element of earth if the need arises,Although the spirit of Fire did not transform into Earth in the anime it did transform into water.

Trivia

 * The Spirit of Earth has a golem/ogre like appearance