a goblin prison warden  

This mob also drops a NO RENT (temporary) key called Droga Jail Key. This key opens the two gates to the jail room, and the cell door to the Stupendous Machine (needed to be accessed in order to do the Greenmist quest).

I'm *guessing* this key was added when the penkeepers and penmasters were moved out to Frontier Mountains back when Temple of Droga was revamped. I have recently tried to open the two gates to the jail area with the Bone Key and the Bone Necklace from the keepers/masters and neither of them work.

-- Troggdor, 50 Iksar Shadowknight of Quellious