The Protector

The Protector (also known as the Ranger) is a man dressed in NCR Veteran Ranger combat armor. He states he is not with NCR, as he said this multiple times. He carries a hunting rifle and a Ranger sequoia. He knows Ben's real name and presumably a lot more.

Background
Virtually nothing is known about the Protector. He is skilled with firearms and hand-to-hand combat; he easily defeats Ben in a fistfight and deflects Twig's Shishkebab attack with his sequoia. Though he is only physically seen in the final episode, the Protector has been indirectly assisting Twig, Ben, and Scar since the beginning; he uses a signalling mirror to guide them to Eastwood (which he later uses to monitor Twig while in town) in Episode Two. It can be reasonably assumed that he was present during Larry's ambush.