(something)-mancy is a class of magic that specifically focuses around control of or over something. Many different recognized forms as exist, as well as countless smaller vagaries.
A few of the major recognized mancies:
- Ecomancy - Power over Nature (specifically plants)
- Anomancy - Power over Animals
- Auromancy - Power over Auras or magical fields.
- Necromancy - Power over Death
- Geomancy - Power over Earth
Each Mancy was developed separately, at different times, and often came about simultaneously in multiple locations, or was re-invented multiple times. The exception is Necromancy, in a class all its own.