USR Special Fleet Security, better known as the Protectors, are a special forces branch of the Navy, who operate in concordance with crew of the ship and the embarked army personnel to provide protection in the event of ship-board raiding. They are also assigned to protect orbital and ground side facilities. Their role is two fold, in that they preform counter-boarding actions, fighting against enemy forces attempting to board their ships in close range, and counter terrorism, stopping terrorist attacks against the fleet. As such, they closely guard many facilities and ships with a vigilance not seen in many Sangheili.