D&D 3.0: Tales from Mystara
Nyx’s Post is a fort of the Ierendi Royal Guard located on Elegy 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).
Both Malpipas Tower and Nyxs Post are part of the Ierendi Royal Guard, but the soldiers that come from Ierendi Island to serve in this island go directly to the fort and rarely visit the town of Nula unless they are locals.
Nyxs Post has even a second contingent of 100 undead that can be raised by the native necromancers if needed.