Ether striders are the war machines of the largest phase spider nests. Their bodies are woven from the same strands of ethereal webbing that phase spiders use when constructing their nests, and are fitted with plates of crimson chitin harvested from dead xill. Chitinous plating notwithstanding, ether striders are only tenuously solid. This is particularly true on the Material Plane, where an ether strider will blink in and out of existence, but even on the Ethereal Plane, the webwork body contained within its exoskeleton is slightly amorphous.

Ether striders occupy a curious place in phase spider culture. While often employed in raids and other frontal assaults, an ether strider's traditional purpose is the defense of the nest and the young that reside there. Phase spiders growing up in large nests often view ether striders as parents of a sort, and have strong familial feelings towards them. In some nests, this feaux ancestral relationship takes on religious overtones, with ether striders serving as animate idols. And even in nests where ether striders are not objects of worship, it is rumored that their creation involves profane pacts with any number of monstrous deities, and the phase spiders that create them frequently serve as clerics.