Feldjäger

Originally the imperial corps of Feldjäger served as the retinue of early emperors on the hunts and countryside trips. Even then their role in preparing the grand imperial hunts sometimes lent them substantial power as the emperor's representatives, and the members were picked with great discretion both due to the abundance of opportunities that such a closeness to the emperor's person provided and due to the prestige of the noble pursuit of the hunt in the thoroughly warlike imperial society of earlier days. 
As time advanced, and the emperors settled to rule from their palaces in the prosperous Thirteen Cities instead of roaming the nation, the Feldjäger found their duties diminishing and were then assigned, as trusted men of their lord, to deliver important dispatches to and from His Majesty. Gradually this service, by its nature placing trusted agents in position to observe the state of local matters, led to the reorganization of the corps in the year 311 from the Founding by emperor Adolf-Wigbold. No longer subordinate to the Master of the Household and instead answering directly to the emperor, the Feldjäger found themselves enjoying total freedom from the threat of civil or criminal persecution, except when sanctioned by the emperor himself, and the lofty status of a Life Guard detachment, entering the innermost circle of His Majesty's guardians and servants. 
Adolf-Wigbold's reform led to increased use of the Feldjäger, mostly in supervisory role. However few in number, they were assigned to oversee important commands and positions, supervising important state projects, billeting of soldiers, customs serivce, mints, the Praesental army, the Household Guard, and serving in the double capacity of the emperor's representatives and informants at the courts of vassal lords, negotiating on a number of trivial matters, often being assigned by their master to negotiate on much more serious matters, watching for any sign of conspiracy, and sending encrypted dispatches back to the court at regular intervals. It is common knowledge among the imperial nobility that the report of treason by a Feldjäger can sometimes lead to hostage relatives being demanded to ensure compliance. 
Locally, Feldjäger are indeed above the law, as they are direct servants of the emperor and cannot be tried except by the Imperial Chamber Court with an explicit sanction from the emperor. While this does sometimes encourage abuse of office, the emperors, usually supported in this by the powerful Masters of Office, who have all reasons to dislike the emperor's own observers, are known to be very willing to investigate reports of said abuse, assigning harsh punishments to the guilty, although the willingness is rather propotional to the scale of the misconduct; while debasement of currency at a mint will be investigated with all due strictness and attentiveness, harsh billeting arrangements in a small village are likely to fail to attract attention at all.