ASOIF: Night's Watch Ranger Trackers
The Ranger Trackers are certainly not the hardest-hitting or most heavily-armored cavalry unit in Westeros, but they are some of the fastest and most agile. These swift hunters are able to get almost anywhere they need to be on the battlefield. Utilized as scouts when not in battle, they also have a keen knack for finding weaknesses in enemy units, setting them up for their brothers to take down.
The Ranger Trackers unit for the Night's Watch brings a swift cavalry unit to a Commander's arsenal. They may not hit hard, and a good Commander will keep them out of harm's way, but their ability to cause enemy units to become Vulnerable is an invaluable resource. Either setting up for a shot from their own recurve bows or a charge from another friendly unit, enemy forces will be wary of the sounds of galloping hooves in the distance.