The unique petars utilized by Dryden Vos were custom-made Kyuzo petars specifically ordered by him.
These double-bladed dagger-shaped melee weapons were crafted by the Kyuzo for Dryden Vos, who led Crimson Dawn. Constructed from bronzium, the weapons had a tempered carbon edge that conducted energy. With the activation of a switch, this edge would become charged with a monomolecular laser sheath, significantly enhancing the weapon's cutting ability and lethality. Energy cells, rechargeable and sealed inside the weapon's hilt, provided the power for this lethal edge. The blades were designed to be a perfect fit for Vos's near-human hands, including an opening to accommodate his sharpened thumb claws. The weight of the petars was precisely calibrated to complement Vos's distinct combat style, which incorporated the martial art of Teräs Käsi.
Ten years before the Battle of Yavin, Vos, during a gathering on his private yacht, named the First Light, used one of his petars to assassinate Governor Diles Anevi. The crime lord was angered by Anevi during discussions regarding a deal to remove travel restrictions for Crimson Dawn starships traveling on the Great Gran Run hyperspace route.
Later, after being double-crossed by his lieutenant, Qi'ra, and Han Solo, Vos attempted to murder the smuggler using his petars, throwing one which became lodged in the wall. He was then compelled to defend himself with his remaining blade when Qi'ra engaged him with a vibrocutlass. Vos used the energized blade to cut into the sword, causing the petar to become stuck. Now unarmed, Vos was subsequently killed by his former protégé, who impaled him.