Ossus

Ossus was a terrestrial planet located in the Adega system of the Outer Rim Territories' Auril sector that was affiliated with the Jedi Order. The planet was orbited by at least one forest moon. Some Jedi scholars made the case that Ossus was the site of the Jedi Order's first temple. According to the Qel-Droma Epics, Ossus was a Jedi retreat and the largest repository of Jedi knowledge in history. At the very least, Ossus housed the Great Jedi Library and a Jedi temple.

In the Qel-Droma Epics, Ossus was decimated during the Cron Supernova, when the Sith Lord Naga Sadow triggered stars in the Cron Cluster to become supernovae. The Jedi managed to save a fraction of the artifacts housed on the planet, such as mosaic floors and the Chronicles of Med'eeth, which made it to the Jedi Temple on the planet Coruscant via nearby Exis Station.

According to legend, what few Jedi survived the blast banded together to survive. Over millennia, those humans became tribal Ysanna, a group of near-humans with a high percentage of Force-sensitivity among them, who regarded it as atavistic magic. The other humans on the planet were considered a minority population.