The Sithicus Imperium

The great city-state/continent that is ruled by Lord Harken. This is a great place to buy awesome merchandise and be generally awesome.

The City
Despite being an Imperium, there is only one city (and a few barely inhabited island territories). The city is very big though, covering most of the continent. The city might not have a name, generally be referred to as "The City", "The Sithicus imperium", or "Cease Your Prattling And Die, Mortal".

The city is highly industrial. Much of the coastline is covered in docks, from which sail dread ships to the nearby islands and Darkwood. The ogres of the Darkwood often preyed on these ships, which often contained magic items presumably scavenged from the area.

Somewhere to the north there is a mine (maybe several) which produce vampiric diamonds for the creation of new liches. The mine(s) and the caravans carrying the diamonds are a matter of great secrecy.

The Continent
See above.

Inhabitants
The city-state primarily consists of liches, vampires, and ghouls/ghasts. There are also countless mindless skeletons and zombies, as well as a sizeable population of live humanoids. Some of these mortals are even citizens!

Lord Harken and at least one lich general are at the top of the hierarchy. The liches are presumably the ruling class, and they seem surprisingly common. The creation of new liches seems to be a priority of the Imperium. Liches lead the armies and provide fire support through arcane magic.

The vampires are very mysterious. Only one vampire lord, Count Drake, has actually been encountered. His role as an ambassador and entrepreneur suggests that free-willed vampires may represent a merchant class of sorts. Count Drake also has several dozen vampire thralls who are bound to his service in his manor.

The most common free-willed undead are probably ghouls (and their elite variants, ghasts). The most typical citizens, they serve as soldiers and laborers. They spend their wages on humanoid flesh (which they must consume regularly) and positive-energy-based intoxicants. While lacking the pure strength and resilience of zombies (particularly zombie ogres), they are deceptively intelligent and adaptable. A ghoul is fast, vicious, and tough - more than a match for a typical mortal soldier. The more experienced and powerful ghasts are like commandos. Both variants can paralyze humanoids with a mere touch, then induce Ghoul Fever with a bite - producing a new ghoul enslaved to the hunger.

Top secret projects
See Manatee Island