The city of Akenion (Ἀκήνιον) is located inside the crater lake on Akainii island. The crater was formed from volcanism instead of a meteor strike unlike other similar locations on Abmarah. The now-extinct volcano crater goes far deep down, with the city built in a circular pattern around its walls. The underwater metropolis is the largest wing of the Aethian Dominion into the Blood Sea, and houses one of the seals into the Elemental Plane of Water.

The circular nature of the city descends deeper than most underwater settlements of the Blood Sea, as cooled lava tunnels connect the crater lake to the outside sea.