Jedi culture was centered at the Eye of Ashlanae for generations, with the city of Knossa growing out from it. Eventually, the planet became home to the fabled Great Library, which stored the sum of the Order's knowledge. When the Jedi Knight Exar Kun turned to the dark side of the Force and became the Dark Lord of the Sith, catapulting the galaxy into the Great Sith War, he attacked Ossus, desiring Sith secrets hidden by the Jedi. During the events this action incited, the Cron Cluster was detonated, spreading a shockwave around the galaxy. Originally a rich, lush world, Ossus was transformed into an arid and toxic planet when the wave struck the planet. While some Jedi survived the blast, transforming over the passing generations into the Ysanna people, Ossus was largely forgotten over t