The guardians were the discorporate essences of inhabitants from the planet Oblis. These inhabitants died when Oblis met its end through destruction at the hands of the Sith artifact, the Darkstaff, millennia of years prior to the Clone Wars. Following Oblis's annihilation, the Darkstaff ended up resting inside a chamber located on the asteroid I-9, situated within an asteroid belt that came into existence from Oblis's remnants. In order to safeguard the Darkstaff and prevent it from being acquired by undesirable individuals, the guardians, in conjunction with several shadow lurkers (Oblee who had been disembodied and transformed into spirits due to Oblis's destruction), took up residence on the asteroid, aiming to thwart any attempts to remove the Darkstaff.
Around 31 BBY, the guardians made contact with the Heroes of Cularin, a band of independent contractors who had journeyed to I-9 while undertaking a particular assignment, specifically within the asteroid's room of six shadows.
The guardians possessed imprecise, shadowy shapes that floated in the atmosphere. They exhibited a more ethereal look when compared to the disembodied Oblee shadow lurker spirits that also dwelled on I-9.