The Duel on Onderon happened around 1000 BBY. Following the conclusion of Darth Bane's important activities at the tomb of Freedon Nadd, he employed a massive Drexl for transportation directly from Dxun to Onderon, drawing upon the power of the dark side of the Force. His apprentice, Darth Zannah, had recently gotten to Onderon aboard the Star-Wake, and was facing peril. Bane showed up just in the nick of time to rescue her from the Skelda clan of Beast Rider.
Bane immediately confronted the Drexl riders, defeating all nine of them in battle. As the aerial fight concluded, Darth Bane and the remaining Drexl plummeted from the heavens, crashing to the earth. Subsequently, Bane explained to his apprentice that his survival of the fall was solely attributable to the armor comprised of newly acquired orbalisk.