There could be ruins off the ancient Valusia , that existed before the great cataclysm that sunken Atlantis. They could be in a top of a mountain or with a cave entrance hidden! The serpent men were alive and not skeletons, which use illusion magic! We could learn a feat that makes illusionary bases or players!? And a new set of armor and weapons.
The kingdom furthest to the west of the Thurian continent. This kingdom was created and initially ruled by the Serpent Men, until they were overthrown by their human slaves. They attempted to control the new human kingdom of Valusia from behind the scenes, using illusionary magic, when mankind’s memories of their past encounters faded. However, the Serpent Men were again defeated in a secret war. Finally they created a religion, the Snake Cult, to do the same thing again and almost succeeded. Their power was, however, eventually destroyed by Kull, an Atlantean barbarian who had gained the crown of Valusia by force.