Tanka was a Trandoshan who was a member of the Revengers, a group that fought the Crimson Dawn criminal syndicate. After Crimson Dawn destroyed the village where Tanka and Ankala Sahm resided, the two joined S'ira, whose own village the syndicate had destroyed, to form the organization, making their goal to seek out where Crimson Dawn was operating and attack its operatives.
While on Calior, where Chief Regional Auditor Cygnus Anton of the Galactic Empire was making demands to the locals while accompanied by Crimson Dawn enforcers, the Revengers were assisted by servants of the Sith Lord Darth Vader, who was also on a quest to eliminate the syndicate. Vader recruited Tanka and the other members of the Revengers as part of his quest.