Ars Magica : Golemsburg
Realm: Magic (Aquam)
Thalassia is a water based realm that seemingly has no concept of fire. They are governed by a cannibalistic queen who enjoys the taste of humans.
They are slavers and trade kidnapped maidens to one another, maidens who remain in the realm for too long will become sirens and lose knowledge of their previous lives.
Their currency appears to be pearls.