Citadel Sealt
A massive, well-defended fortress on the Quasi-Elemental Plane of Salt owned by the Doomguard, a faction from Sigil. It was dug out of a single massive salt crystal in the Sodium Peaks, directly adjacent to the Negative Energy Plane.
This citadels's Doomlord is Kelch deHoder, one of the faction's accelerationist sect, seeking to speed the rise of entropy in the universe. It is believed that the Doomguard use this citadel for secret projects dedicated to that end.