Shadow Sage

No the shadow sages do not exist, they are a myth made up by those incompetent enough to create decent security measures. If individuals have stolen information they would better look at their rivals. The only things we do is procuring artifacts of ancient times that we are far better equipped to examine and study. We are just the first most of the time because are people our decently trained. Don't blame your failings on another.

— High Sage Syronikir

Some believe that a part of the Keepers has a hidden agenda. According to them members of this secret division send spies all over the world. So far no one has ever verified there existence though. If the people only knew that they were actually right about this myth...

Function

The shadowsages are indeed an existing branch of the Keepers. And although that the myth surrounding them is partially correct they do focus on other things in reality.

Spies looking for chaos

An extensive spy network is maintained by the Keepers but used in a different manner than governments would do. The Keepers care very little for political intrigue or financial knowledge.
The people who actually should worry about being watched are those that practice the arcance arts, especially the more powerful casters. In itself the Keepers don't think there is anything wrong with practicing magic. They even practice and research it freely themselves. What they, however, have a big problem with is the practice of Chaos magic.
Since the Keepers know a lot about the various cataclysm that were caused by Chaos magic they want to prevent such future events in any way they can. One of the task of the Shadowsages is to track down any Chaos Crystals pop up. The information is procured by lesser shadowsages or informants.

Yamaderis misplaced this image by Kefkjaco with heroforge

by Rexard

Removing Chaos Casters

The more skilled shadowsages get a dangerous task, 'removing' the chaos casters. To complete such tasks they have been trained for years in the use of magic and covert techniques.
Chaos casters are too dangerous to be left alone according to the Keepers. Removing them is the only solution. This does not necessarily mean killing the casters, that is an option that is only taken for the most dangerous individuals or if there are no other possibilities.
The most used method of removing a chaos caster is by implementing a condition called magic suppression. Similar methods exist in different parts of the world but the Keepers have improved it to such a degree that they are able to stop an individuals from using magic for the rest of their lives.
Many would find these methods extreme but it is likely that the shadowkeepers have saved countless lives and regions thanks to their actions.

Recovering Artifacts

Another important function the shadowsages perfom is the recovery of ancient and powerful artifacts. In general they Keepers don't want any type of artifacts that can be dangerous to fall in the wrong hands. But most of the time it comes down to Prime Asmer technology.
In the past ancient Prime Asmer technology has been used to wreak havoc in unexpected ways before when it was used as a weapon. These types of events are the shadowsages trying to prevent in the future.
Shadowsages tasked with recovering artifacts often join adventuring parties or mercenaries but can just as well be send out on expeditions funded by the Keepers themselves. Anything that is deemed dangerous is brouoght back to the Keepers for further examination.

Asmer God by Endless Space, Amplitude Studios

Training

Yamaderis misplaced this image by Kefkjaco with heroforge

Selection

To be selected for the position of shadowsage one has to first be a member of the Keepers already. Only members who are known to be loyal are able to receive an invitation. The older shadowsages mainly look illusion enthousiasts and those with curious minds.
Before they are told that they could potentially join the shadowsages the candidates are invited to a sort of exam. To them it seems like a normal test that they do to see if they can get higher positions. The results of the tests do determine those up for promotion but also have a hidden reason.
Those who did well on the reasoning and attentiveness tests receive the invitation and an extra interview to determine if they are made for the job.

Becoming shadowsage

The training to become a shadowsage lasts at least 4 years. During this time they learn how to practice illusion magic and influence other people's minds to a degree. Additionally they are thought to move quietly or to not be noticed in crowds. Also their social skills are improved to get away with lies if necessary.
By the time they are done, they are masters of disguise and deception. Before officially becoming a shadowsage the trainees typically get an easy assignment to prove their worth. Once they have completed their first task they officially become shadowsages.

by Rexard

Further Reading