From Destinypedia, the Destiny wiki
Sentinel Servitors are powerful Servitor units from the House of Salvation. They are deployed in the Deep Stone Crypt Raid to sabotage and disable the Augment Terminals, which prevents the transfer of augments.
They are first seen in the Crypt Security and later deployed in the Atraks-1, Fallen Exo boss battle. Elimination of these Servitors should be given top priority.
List of appearances