A brilliant and reckless scientist who joined Discovery to study the Dark Matter Anomaly and then went rogue with Book to destroy it.
Ruon Tarka was a gifted, abrasive scientist brought aboard Discovery to help determine who had created the Dark Matter Anomaly, the gravitational phenomenon that destroyed Kwejian. He built a model of the anomaly and became convinced it should be destroyed rather than negotiated with.
When a Federation assembly voted for first contact with the anomaly's creators, Tarka fled with Cleveland Booker, obtained the rare isolynium his weapon required, and fired it on the anomaly's controller, destroying it only for a new one to appear. He revealed that his real aim was to seize the anomaly's power source and use it to travel to a peaceful parallel universe, where he hoped his friend Oros, a fellow prisoner from his past, had escaped.
Tarka smuggled Book's ship aboard Discovery, took Jett Reno hostage and enlisted General Ndoye to break free. As he tore into the power source of Species 10-C, Ndoye rammed his ship with a shuttle, killing him.