The Elemental Plane of Water!

One of the four Elemental Planes.

In Feinan, the four Elemental Planes were mysterious planes, even more mysterious than the Astral Sea, Hell, and the Abyss.

Even a powerful Legend Wizard would find it difficult to travel to an Elemental Plane.

Because the four Elemental Planes guarded themselves tightly against outsiders.

Even though many Wizards summoned some Lesser Elementals, these Elementals would loyally carry out their orders, but wouldn't leak anything concerning their Elemental Plane.

The Elemental Planes were ruled by four Sovereigns who were immortals and were said to have been born along with the Universe.

They guarded the heart of each Elemental Plane.

The power of the four elements was independent and chaotic, but when merged, it became the power of Order.

In other words, it was the Elemental Planes that supported the Astral Sea while also being the source of the power of Order in every plane, opposing Chaos power. It led to both sid