Who are the Sentinels in the novel, Unleash the Night?

Out of the Arcadian patrias are born the Sentinels. They are the guardians of man and Were-animals. Only a select few are born to each patria. They are the strongest Were-Hunters and pursue and execute Slayers or those found guilty by Omegrion. A "geometric design covers one side of an Arcadian Sentinel's face once they reach maturity, but the Sentinel can hide the design if they choose to."