Speaking of Big Fish -- The Plane of Elemental Water

The Plane of Elemental Water is one of the four elemental planes undergirding the physical reality of Arden Est, along with the planes of fire, earth, and air. The great ocean, Terminus, contains many portals here, as do some of the larger lakes such as Lake Leriel in Lyonia. All of the known gates open into the upper layers, though there are rumors of a gate that leads to the great city of the Marids.

The uppermost layers of the plane are well-lit and pleasant. These are mainly inhabited by merpeople, nereids, and other water spirits. It is perfectly hospitable here as long as you can breathe water, and bubbles containing the retreats of various archmages are not unknown. Poseidon still has influence here, though it is not directly a part of his domain, and Vassa can sometimes be found sailing on the surface, or leading forays against Sahaugin undersea.

As you go deeper, however, it eventually begins to grow darker, casting the surrouding area into a sort of twilight. As the pressure begins to become uncomfortable, the Marid hold sway, ruling from the City of Glass, Dumat Al-Jandal. They do not suffer many outsiders to travel through their waters, but they are said to be a proud people and susceptible to flattery.

Beneath the realm of the Marid, the light ceases to illuminate, and the pressure becomes crushing. Strange creatures inhabit these depths. Schools of undead dolphins swimming upside down patrol these waters, and demon hunting parties searching for shipwreck elementals are a common sight. Shipwreck elementals are formed from the souls of drowned sailors, and appear to be a common water elemental but for the pieces of wrecked ship swimming in their body, swirling around drops of blood.