Large, walled or otherwise barrier-protected cities that serve as primary locations for populations of alien species to live in, work at, and call home. These citadels are always fortified with a number of armaments and a dedicated military force to protect against outside threats. There typically exists one or two citadels per province or territory within each nation, along with a handful dispersed across the Azuran Neutral Zone, including Azura itself.
In addition to the typical city name, citadels are also given a title, similar to those given to outstanding individuals, that help to highlight the most iconic attribute of the city. Halitas the Golden Citadel and Arcanum the Mystic Citadel are two examples of such titles.