Garnac was the ruthless leader of a pack of Trandoshan hunters on the Third moon of Wasskah. He and his subordinates enjoyed capturing beings and hunting them for sport, particularly Jedi Padawans and younglings.
Garnac's skin was embellished with shades of grey and green, making him easy to identify among other members of his group. The horns on his head were also tinted bright orange.
Garnac was an experienced hunter and was seen using a variety of weapons including sniper rifles and throwing hatchets. He also wielded great physical strength and body mass, which gave him an advantage in most close combat situations.
On Wasskah, Garnac assisted his son Dar in claiming his first Jedi kill. Catching the scents of both Kalifa and Ahsoka Tano, Dar moved in to kill the two padawans. In defense, Ahsoka attacked Dar, kicking him off a ledge to his doom. Enraged by his son's death, Garnac shot Kalifa with his sniper rifle, killing her.
Garnac was called in when one of the Trandoshan prisoner transports had crashed. He discovered the Padawans had destroyed it and freed its one prisoner, Chewbacca. He also assisted in trying to defend the Trandoshan fortress from the Padawans and the Wookiee reinforcements that arrived via Tha Halo. Garnac rushed back into the fortress where he was confronted by Ahsoka; they fought and Garnac used an axe and knife to attack her. After a struggle between the two, she Force-pushed him onto his back and Tano declared Garnac beaten. He reached for his gun, but was consequently Force-pushed by Ahsoka, sending him flying through the thick doors and off the balcony, falling down to the lower deck, killing Garnac.