The Emerald Spire Superdungeon
Six miles northeast of Fort Inevitable lies one of the deepest and strangest dungeons to be found anywhere in the lands of the Inner Sea—the Emerald Spire. Like an iceberg, this weird structure shows only a small portion of itself above the surface; level upon level of hidden vaults and mysterious crypts lie buried deep below the ground. Few of the people living in Fort Inevitable or the surrounding lands have even the slightest inkling of the dungeon’s true extent, let alone its astounding age.
Standing in a wide clearing within the Echo Wood, the Emerald Spire is the ruin of a large Azlanti tower that appears to be made of green glass harder than stone. The upper portions of the tower were destroyed long ago, leaving broken, half-melted glass blocks lying jumbled around the tower’s perimeter and the ground nearby. The site is well known to locals from both Fort Inevitable and Thornkeep, and many travelers passing through the Crusader Road area make the trek into the forest to look on the ruins—from a safe distance. The Spire’s ruins are known to be infested with dangerous monsters, and the surroundings attract an unhealthy number of bandits, raiders, and hungry predators.
The history of the Emerald Spire is largely unknown in this day and age. Few scholars have ever studied the place—as far as the local people of the River Kingdoms are concerned, it’s enough to know that the Spire is old, strange, and dangerous. The Emerald Spire is widely reported to be an Azlanti ruin or thought to be some kind of retreat or workshop for the Azlanti who once lived in the Echo Wood.
THE SPIRE GLEN
The Emerald Spire stands in a broad, raised clearing in the southwest reaches of the Echo Wood. This open area is known locally as the Spire Glen. The glen is almost perfectly circular and centered on the Emerald Spire, as if some unseen hand had long ago drawn a border around the old tower with a compass more than 500 yards wide. The trees of the Echo Wood crowd up against this unseen border and suddenly halt—nothing larger than a sapling grows in the Glen.
Few indeed have ever seen it happen, but the Emerald Spire occasionally generates invisible gates or portals that drift through the Glen, briefly linking its deeper levels to the surrounding countryside. This means that once in a while, some fearsome denizen of the deep dungeon is gated out into the Glen to wander or rampage. Likewise, hapless travelers have just disappeared while in the Glen, inadvertently stepping into an unseen gate and finding themselves in some deep level of the Spire. These mysterious gate openings seem to be more common at night, and some claim they vary in frequency with obscure planar alignments.