Shadestriders are soldiers of the Aethereal Realm that carry out the Reapings.
They appear at dusk, materializing from the bones up in a vortex of wind. They steal victims' life energy by pulling it away from a victim’s chest and eating it, leaving the body a withered corpse. Shadestriders are equipped with have obsidian-like armor and weapons, and their faces are veiled. Under the veils, the top halves of their faces seem to be like that of a normal person, with the bottom halves/jaws described as being like clear glass of various colors (purple, blue) with the bone visible underneath. They seem to recognize various languages on an individual basis, but speak in a screeching language (B1E1).
They either have a high AC, nonmagical damage resistance, or both, and possibly some regenerative ability. Silver may have stronger effect. When destroyed they de-materialize. They are sensitive to light and seem to melt at exposure (B1E1).
During the Harvest they seem to materialize singly or in small groups over a period of time in a localized region, and can also summon hunting dogs. Their general strategy is to seek people out apparently at random, stalk them down, and steal their life force, using their dogs to chase runners and melee weapons when they meet resistance (B1E1).