The Star Core was a small object small enough to fit into a backpack yet powerful enough to power a planet, or even a new Death Star.
The Galactic Empire began researching this technology in the city of Restuss on Rori. During its developmental stages, the Rebellion heard of this object and began amassing troops outside of the city. The Empire quickly evacuated the city of Restuss and prepared for battle. During the climax of the Battle of Restuss, something went terribly wrong with the Star Core. In its developmental stage, it exploded, destroying the once great city of Restuss.
- Star Wars Galaxies: An Empire Divided