The spectral guardians were ethereal spirits tasked with protecting the Jedi monument located on Rhen Var. While searching for Ulic Qel-Droma amidst the Dark Reaper crisis, Anakin Skywalker came across them encountered as they defended Qel-Droma's final resting place. Prevented from gaining entry, Skywalker was compelled to engage them in combat using a TX-130 Saber-class fighter tank. Ultimately, he was able to disperse them by obliterating their tombs, the source of their abilities. Following this, he went on to obtain the information he was after.
These enigmatic beings possessed the ability to phase through solid objects and materialize weapons composed of pure energy from the surrounding atmosphere.