The Tower of Troubles is a Mages guild where young wizards and sorcerors are trained in the Art. It arose as a compromise between the gods of Bareel and the human practitioners of magic.
Specially treated troll flesh dried in strips like jerky which heals in small doses.
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.