The Underwater Palace
The merfolk of Hercyna are the sole survivors of a civilisation founded 
centuries ago underwater.  Its distinctive coat-of-arms is still just 
about visible on the walls of the self-styled palace, formed out of the 
partially-flooded cave systems carved out by the river underground.  An 
apolitical people, the mermen and mermaids farm subtropical fish on the 
rich coral beds and trade with the overground world via messengers, their 
currency the semi-precious treasure trove they fiercely regard as their 
own.  The Merqueen is trusted as the spokesperson of the folk, and as 
guardian of the vast wealth hoarded below ground; her people will do what 
they see necessary to keep her safe from the ill-will of outsiders.  
Essentially, however, they are a friendly and magical folk, with knowledge 
of healing and vision often surpassing that of human minds.