The Age of Worms
Fiendish green dragon that once served Tiamat. She was exiled to the Material Plane, where she kept a low profile until she eventually sought out her old cohort Dragotha. She was resistant to magical damage, cold, and fire, and immune to acid, paralysis, and sleep. She had the ability to smite Good.
She was, invisibly, guarding the Citadel of Weeping Dragons when the party teleported there on the 12th of Reaping, CY 601. Despite her attempts to drop him a thousand feet into the canyon at Kongen-Thulnir, Archie managed to almost single-handedly (along with an opportune attack from Tyrrell) kill her just as the party escaped into the Citadel.