Built on a rocky islet in the western waters of its surrounding lake, Tirnmere Fortress is an ancient and isolated structure whose oldest existing walls are thought to have been erected by the Ervuolians around 3,000 BA as a refuge against the anticipated Eighth Ruin. Subsequent work over many centuries enlarged and reinforced the structure with towers and rocky ramparts, but it was abandoned in the early third century YA and is now a ruin, frequented only by occasional antiquarians, adventurers, and bandits.
Depending on the level of the lake, the fortress may sometimes be approached by foot from the west along a narrow, muddy isthmus.
