Perched on the lip of the sheer abyssal walls, the city of Cthonos overhangs the deeps. The center of Atalan knowledge, Cthonos boasts many schools and colleges of both academic and practical disciplines, as well as the largest library in the Atalan Alliance. The architecture, like the seascape, is solemn, austere, and monumental. Massive, interconnected buildings form a single, self-contained, arcology. Aside from a few air-gardens, the city is entirely flooded.

About halfway down the walls of the abyss, sirens build homes, shops, and other buildings that cling to the abyss walls like barnacles.The inner rooms are usually dug into the rock wall. Slender bridges span the gap, offering safe places for people and goods to cross without fear of attack from below. Below these are the mines - deep shafts into the walls sides of the abyss from which they get both magical and mundane ores. Between the homes and mines are the forges and workshops where the ores are smelted and refined. Large, ley-powered elevators help move tools and ores up and down.

The deepest levels of the abyss, where the cold and darkness are absolute. Deepsea vents spew magma, toxic gasses, and raw Ley energy. The ley energy has infused the sea bed and sealife with strangeness. The seascape seems to shift when you’re not looking. Strange voices whisper in the water. Bizarre monstrosities lurk in the darkness. Most have never been seen and are known from the scars they leave on sperm whales and the occasional undersea vessel that travels too deep. Despite this, many have and continue to brave almost certain death because it is said that somewhere in the midnight waters is an active Ancient site. But, so far the, depths yielded nothing beyond the occasional relic or artifact.