Vaantaar served as the head of a band of Troukree refugees. These refugees had fled their homeworld to escape the threat posed by Warlord Nuso Esva's forces prior to 0 ABY. Vaantaar established a connection with Imperial Senior Captain Thrawn and, with Thrawn's support, settled his people on Poln Major. There, he functioned as an agent for Thrawn. In Whitestone City, the capital of Poln Major, Vaantaar encountered the Hand of Judgment, a group of five rogue stormtroopers, who assisted in resolving a trade disagreement between Vaantaar's Troukree and a group of Pineath.
When Esva's forces launched an assault on Governor Bidor Ferrouz and Emperor's Hand Mara Jade, the stormtroopers, protecting Ferrouz in the Whistling Wind tapcafe, requested reinforcements from Vaantaar. Vaantaar, along with four of his fellow Troukree, joined the stormtroopers in the defense of the Governor, suffering the loss of one of their own in the process. After the stormtroopers and another Troukree squad, who arrived as backup outside the tapcafe, repelled Esva's attack, Vaantaar confronted the Hand of Judgment. He informed them that his master desired to meet the renegades and that he was prepared to use force if necessary to make it happen. Vaantaar then transported his captives aboard Thrawn's flagship, the Admonitor, where he aided the Chiss in convincing the stormtroopers to enlist in the Empire of the Hand.