The Battalions of Zhell came into dominance on Coruscant by waging war on the Taungs for centuries. During one of these battles, the Battalions of Zhell suffered a near extinction level defeat when a volcano destroyed their main city. The volcanic ash would fill the skies of Coruscant for two years, so that the Taungs adopted the name Dha Werda Verda or the "Warriors of Shadow" for themselves. The battle was immortalized by an epic poem with the same name.
The Zhell eventually recovered and drove the Taungs offworld—the Taungs fled to Roon. Since Coruscant is considered by some to be the home world of Humanity, historians have hypothesized that the Zhell species may have been the ancestors of the Human race in the galaxy.