My father is slain. His house is broken. His sword is shattered, and his axe has been rent apart. But his blood lives on.
The restless shade of a terrible demon of an age long since dust.
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.