River Acheron
Told of mainly in legend, the River Acheron is said to flow across the bottom of Ocanthus, in Acheron. Allegedly made of tar with iron plates floating in it, the River Acheron is inhospitable and vile. Symbolically speaking, it’s the entrance to the Lower Planes, as many sages claim that Acheron (the plane) moves away from Evil and towards Law as you descend the layers, and so Ocanthus must be the closest to Mechanus, they say. Acheron is also the home to Charon, the Boatman of the Lower Planes. This enigmatic demipower is rumoured to be an ancient yugoloth of unknown race who commands—or possibly trains—the marraenoloths in the arts of pragmatism and exploitation. His representative in the wider area of the Lower Planes is an ultroloth who looks like a large marraenoloth and who calls himself Phlegyas. Be very careful when dealing with either of them.
Source: Alex Roberts
