While the Nova Blades on Rishi make a sound income from extortion and slave trafficking, their strongest growth category has been in mining the fossil fuel exonium. In its solid state, exonium coals are easy to ignite and burn for a long time at a high, stable temperature. In fact, the Rishii have long used exonium to keep warm and render fish fat. Its real value, however, comes from refinement.
In attempting to return to the stars after being stranded on Rishi for an extended period, the Nova Blades found that refined exonium not only made a suitable fuel for propulsion systems but also acted as an effective reactant fuel for their hypermatter drives. Because of its value, the Nova Blades tried to keep the origin world of exonium a secret, but now anxious prospectors have begun to trickle in from all over the galaxy. Whether these prospectors will pay the Nova Blades' recently introduced Exonium Export Tax remains to be seen.