Dark Side wraith

The Dark Side wraiths were all that were left of the six beings who were once the rulers of an unknown jungle planet which the Dark Side pyramids were located on. They were shadow forms of the ancient Dark Side priests who were still clinging to half-life through the powerful dark side emanations of the Altar of the Dark Side. They were visible only to Force-sensitive individuals.

Text and facts from the “Dark Side wraith” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.