These pitiful creatures are the creation of their vampire master. From a distance (or in the dark) they appear to be normal folk but up close their pallid skin, baleful red eyes, and sharp fangs betray their true nature.
Vampire Spawn have incredible strength and resiliance but are vulnerable to radiant damage. The heroes encountered a coven of six Spawn under the ruins of Castle Spellgard. They were in the service of the vampire Barthus.