Tanka, a Trandoshan, belonged to the Revengers, an organization dedicated to combating the Crimson Dawn criminal syndicate. Subsequent to the destruction of the village shared by Tanka and Ankala Sahm at the hands of Crimson Dawn, they allied with S'ira, whose village had also been eradicated by the syndicate, establishing the Revengers with the express purpose of locating and attacking Crimson Dawn's forces.
During an operation on Calior, the Revengers received assistance from agents of the Sith Lord Darth Vader, who was similarly engaged in eliminating the syndicate. This occurred while Chief Regional Auditor Cygnus Anton of the Galactic Empire was making demands of the local population, supported by Crimson Dawn enforcers. Vader subsequently enlisted Tanka and the other Revengers as part of his mission.