Sentinel is the Advanced Recon Force (ARF) detachment of the 597th. Sentinel members work in the field ahead of the force elements, directing and updating the platoon with valuable recon, and surveillance intelligence for battlespace shaping. ARF Troopers are the silent warriors, changing the course of the battle with a few well-placed map markers, rather than a few well-placed plasma bolts.

To join Sentinel you must be SCT+ and have a Rifleman qualification, the marksmen qualification and the RTO qualification.