An ancient people built mystical fortresses made of melted stone; from the wall’s these fortresses defenders appeared to burn with a powerful energy and strike at their opponents with a supernatural force. Today most of these forts are abandoned and the art that made them lost.
The spirit of a creature trapped in amber cannot escape to it’s afterlife / next incarnation / whatever.
Such trapped spirits can be contacted by those who know the right rituals and magical power derived from them – typically the power to control one individual of that species.
Can by quite powerful if the creature is a colony insect (ant, bee, wasp, etc) – simply control the queen and you command the whole colony.