Citadel Altaerein - Empty & Clean presents the Hellknight fortress stripped of occupants, debris and encounter-specific clutter so the architecture can do the work on its own. Thick stone walls, connected halls, courtyards and numerous rooms remain, but the cleared surfaces make the stronghold easier to repurpose as a functioning headquarters rather than a ruin frozen at one moment in the adventure.

For a GM, this version is especially useful after the party claims or restores the citadel in Age of Ashes: Hellknight Hill. Rooms can be assigned new purposes, furniture and tokens can be added without fighting against baked-in damage, and the multi-section layout provides enough space for workshops, storage, meetings and private quarters. Outside the Adventure Path, it is a flexible blank fortress for any campaign that needs a substantial stone keep with a coherent floor plan and no predetermined occupants.