Aakas

First encountered under the ancient city of Aakas, it is presumed that the Aakas Defenders were put in place to protect whatever lies in wait in the underground environment. Little more is known about them, and research efforts are slowed by the fact that it is difficult to study anything about them without the imminent threat of death.
There is much conjecture about the differences and similarities between modern day humans and ancient Arkadians. IFN and Archaeological Society researchers suspect the Arkadians may have been the ones to set up the Sentinels.
There may be more history here then first meets the eye.