Olleth: This underwater slave city was once ruled by the Arcanum of Olleth, a group of spellcasting morkoths. In their arrogance, the morkoths ambushed a kuo-toan delegation on business of the Sea Mother. Half the embassy was slain and eaten, and the survivors were brought to Olleth as slaves.
The kuo-toas pledged to the Sea Mother made poor slaves, for their resources were only a prayer away. Within a few years, the Arcanum suffered a series of disasters secretly caused by kuo-toa priests.
The Spellplague was the final straw. One in three morkoth mages dissolved in blue fire, and the survivors lost their spellcasting ability. The kuo-toas rose up and claimed the city for themselves. All morkoths were purged, though other slave races were allowed to remain—under new masters.
The kuo-toas enjoyed only a short span of independence. Olleth pledged itself to the Abolethic Sovereignty not long after the city of Xxiphu rose.
The semidrowned streets of Olleth are a place of nightmare. Rituals are presided over by mad-eyed kuo-toas, with sacrificial victims taken from far and wide to hallow and empower the Sovereignty.
