Atigeo Sea is one of the few inland seas to exist on Hell. It is in fact one of three inland seas made of water, and is the biggest. The sea has came to be through constant eruptions from nearby volcanoes who's water vapour condensed and filled the valley that the Atigeo Sea once existed as, and therefore created the inland sea. Its temperature sits at about 29 degrees Celsius.
The Atigeo Sea is on average about 410 metres deep, 482 at is maximum depth. The Sea stretches 990km at its widest, or 615 miles. The sea has many valleys and mountainous regions, with a very diverse range of depths that fluctuate around the sea. Towards the north are more valleys, which have been caused by mass hydraulic action; the areas right at the north pole are just cold enough for ice to form, and the constant thawing and freezing based on temperature kept on expanding the valleys into larger, deeper areas, which eventually filled and formed part of the sea.
The Atigeo Sea hosts a small variety of creatures, both plants and animals. Thermal lilies and other plants have the ability to generate thermal energy, usually from thermal spires that dot the seabed.