A Guardian Spirit was a type of parasite with telekinetic abilities. They would inhabit dead bodies and gain control over them, making it seem as if the body had came back to life. They could also reanimate bodies when not inside them, although they could only do this less efficiently. Their parameters of existence were confined to within close proximity of the dead, as they could not live outside a host body for long without dying.
Two Guardian Spirits were released by Valin Draco into the library of the Almas Academy and they inhabited the decomposing bodies of a group of salvagers called the Stalfonauts and a group of bounty hunters that had been led by the Kel Dor Jacen Yar. However, both spirits were killed by a group of Alderaanian Resistance fighters who had came to the Academy.