Black Masks

Black masks are captured criminals with desirable skills who have agreed to work with the magistrates for a commuted sentence.They wear enchanted collars which tie them to the service of the magistrates and can be activated to kill them should they break the oaths that they take as part of the process. They are distinguished from the magistrates by their Masks, which are black as opposed to the traditional gold.

Many who display good behavior are given a significant amount of freedom and even a simple wage with which they can purchase or trade for amenities.

Runestone
The enchanted collars around a Black Mask’s neck serve to curb unacceptable behavior. At a touch of a runestone, the collar can sap the vitality from an individual entirely. The criminal suffers one level of exhaustion per level of severity indicated by the runestone holder.

Level Effect
Due to a system of failsafes, there are three designated runestones to every collar. One is held by the Blackmask’s keeper, a second by the Precinct Captain, and the third is locked away at a designated vault in the city Palace.
 * 1: Disadvantage on ability checks
 * 2: Speed halved
 * 3: Disadvantage on attack rolls and saving throws
 * 4: Hit point maximum halved
 * 5: Speed reduced to 0
 * 6: Death

Oaths
As part of their oaths as Black Masks, they may never:
 * 1) Leave the city
 * 2) Stray further than 100 feet from a magistrate
 * 3) Kill an officer of the guard or official of the local government
 * 4) Disobey a direct order from a rune-holder.