The planet known as Phemis is a rocky world in a system of the same name, which itself is on the outskirts of the Corellian sector. Despite the great population and traffic of the surrounding sector, Phemis itself has remained a backwater world of little interest to the galaxy. It’s difficult terrain and limited water supplies make it a poor choice for a colony, and the harsh rock formations that cover its surface contain few minerals of any significant value. As it stands, a small number of mines operate on its surface to extract what limited resources the planet has to offer. These mining companies have claims dating back to the Old Republic, and as such are governed by their home planet’s policies and laws, so no local government is needed. The one thing that makes the planet special was widely unknown to the galaxy, for Val Isa, the Jedi who discovered it, was slain before she could return the information to the Old Republic.
Nestled into a canyon midway along the northern hemisphere, there was a series of caves that housed rubat crystals, a rare form of kyber crystal. These crystals were sought after for the construction of lightsabers, every bit the equal of their cousin, the Ilum crystal. Val Isa had been doing geological surveys, specifically looking for crystals to help with the need for the Jedi weapons during the waning days of the Mandalorian Wars. Before she could relay the information to the Republic, however, her ship was besieged by the wife of Mandalore the Ultimate, known as Lady Mandalore, and her warriors.
It wasn’t until almost two decades after the Galactic Empire was established that Imperial Forces, operating on a tip from the local miners, identified the presence of the crystals and set up a quarantine of the planet.