Cave Spiders were offspring of Syrkrosh the Spider Goddess. Cave Spiders inhabited the Tain, but also inhabited other parts of the world. When Kyrilla led her Ops group to destroy Cartucke, he commanded many Cave Spiders to ambush Kyrilla's forces. The Cave Spiders would also harass Light and Dark forces inside the Tain, however, the Cave Spiders did not harass the Dark under Cartucke.
Many Cave Spiders had a Spider Queen which could stun opponents with her poison. These were larger than other Cave Spiders and were often considered more deadly.