Ant Castle

This fortress, called "Sternvakt" or "Star Watch" in the old Skaldic tongue, once watched over the northern part of the Badlands. Its purpose seems to have been to contain some sort of eldritch horror, known by the inhabitants as the "Star Fiend," as well as serving as a more mundane fortification.
Since the fall of the continent's human civilizations, the structure was haunted by the ghost of its last commander, Rhydian Firebeard, who died to the Bane after sending his men away to Kaldaven in hope that they might find a cure there. In relatively more recent times, it was occupied by a colony of giant ants, commanded by a Tyrant Jelly composed of an ant queen larvae and an ooze that had manifested out of the ectoplasmic emanations from within the vault.