Landskeeper
A Landskeeper is a magician from the Marches, who uses magic to support the territories or the nation as a whole.
Threshers
Threshers are Landskeepers who dedicate themselves to tracking down, exposing and destroying practitioners of magic who bring harm to the folk of the Marches.
A few Threshers expand their interests to include the rest of the Empire, looking for villains outside the borders of the Marches whose wickedness threatens - or may eventually threaten - the innocent folk of their Nation. These Threshers have an interests in groups such as the circle of sinister sorcerors called the Volodya, or the most powerful barbarian shamans, who threaten the Marches by dint of the threat they present to the entire Empire.