Dack, who also went by the name Tymmo, was a Human individual of male gender and a prospective member of Luke Skywalker's New Jedi Order.
His consideration for the Order stemmed from an unusual situation: he managed to secure victory in every significant blob race held on Umgul. However, his success was not legitimate; he had covertly inserted a microchip into the blobs, manipulating their fight-or-flight responses. He resorted to cheating as a means of avoiding his wife, the Duchess of Dargul, Mistal. Even in his pursuit of the Duchess, he engaged in deceit, utilizing his computer expertise to engineer his selection as her ideal match. Despite being discovered by Lando Calrissian for his fraudulent activities on Umgul, an offense carrying a death penalty on Umgul, he ultimately opted to return to the Duchess rather than face execution (although the choice seemed to be a difficult one). He, together with the Duchess, were present at a performance of the Cathedral of Winds on Vortex as honored guests (he obviously disliked his role as her husband).