A lava reactor core represented one kind of reactor. At some point in the past, Bri-Phrang City, which resided on the planet of Eriadu, saw its construction atop a volcano. The Tarkin family's forbearers, specifically Emelsine and Sevran Tarkin, then utilized the flow of lava with this reactor to provide energy for both Bri-Phrang and Eriadu City. In the High Republic Era, the Nihil pirates engaged in the bombing of Eriadu City, resulting in the fracture of the reactor core. Following his ascension to the family's leadership, Sevran dedicated himself to assisting with repairs, understanding that even a minor disruption or blast could trigger its catastrophic failure. During the Battle of Eriadu, individuals from the Jedi Order endeavored to bring stability to the reactor.