Orodruin, the Black Isles
Called the Black Isles, Orodruin was once the Namyrian capital, but was corrupted by Felled’s taint. Today, it is a blackened ruin of what once was, and is the home of baalgûl.
The baalgûl originate from the corrupted lands. Baalgûl do not employ a navy, since they have an aversion to water. Instead, they travel from the islands to every corner of the world using an immense network of caverns and deep tunnels called the Hollow.
Orodruin is located north and west of the main continent, and almost directly west of Hibernia. Because of its close proximity to Estermark, baalgûl are particularly prevalent in that country. All the more so since the stonefolk also delve deep into the earth, sometimes opening passages to the Hollow. The First Order and the Hammer have a strong presence in Estermark because of the frequency of baalgûl attacks.
Hibernia is relatively close to Orodruin as well, and baalgûl frequent the passages of the Howling Mountains and the Stonecliff Mountains, though they have not appeared in great force since the battle of Shadowpass a hundred years ago.
Since the black isles are far north and west, the farther south and east you go, the rarer baalgûl sightings become; baalgûl must travel a long time to reach anything in Sul Jahir. This is one of the reasons why the First Order has little to no presence in the south. Almost all southerners go their entire lives without ever seeing a baalgûl or knowing anyone who has. This has driven the baalgûl to myth in many lands.