D&D 3.0: Tales from Mystara
North Keep is a fort of the Ierendi Royal Guard located on Ierendi Island of the Archipelago of Ierendi. Each of these forts usually holds 50 soldiers to patrol the island and protect their citizens and visitors. The fort is usually construct on stone and wood and equipped with at least a siege weapon (to protect them against sea attacks).
North Keep was originally built by King Greeg The First of Ierendi for the survivor members of his crew to live in. The King provided whores, ale and food in large quantities. His men use to party and get drunk at the place and had occasional visits from Greeg.
The same year that Greeg died, the full compliment of the keep (about 25 people at the time) were poisoned. All of them died.