Underrealm barrier

The Underrealm barrier was a subterranean blockade of Raia'dalam erected by adventurers against the Tsol'teth in 734 AF with the help of Parni deSangre, the mage Yudhishthira, and Swordmaster Colbey at the close of the Second Black Wave.

The energy of the barrier dissipated daily, gradually seeping into the lifeforce of living denizens. Hunting and killing denizens caused this energy to coalesce into barrier shards, which had to be supplied to the barrier's foundation stones constantly to keep it from failing.

The Underrealm barrier did fail in 798 AF, shattered by the might of the Divine Avatar Ama-maalier, launching the Third Black Wave upon the overland.