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Arawn's Great Hall contained the throne room where Arawn Death-Lord held court and conjured unspeakable enchantments. From without, the edifice glittered darkly "like black, polished marble"; the black banner of the Death-Lord flapped above it when he was in residence.

Arawn's Throne Room (interior)
Arawn's Throne Room (interior)

Inside the Hall was his throne, seat of power for the Ruler of Annuvin and location of The Iron Crown of Annuvin.