Yerk was a male Human who lived through the Cold War era, a conflict between the Galactic Republic and the Sith Empire. During this period, he made his living as a trader on Nal Hutta, a planet that had become the adopted homeworld of the Hutt species. In the industrial town of Jiguuna, which was under the control of the Hutt crime lord Suudaa Nem'ro, Yerk operated a small market stall. This stall featured shelves stocked with various goods for sale, notably including specialized armor. As was customary for all merchants in Jiguuna, Yerk was obligated to remit a portion of his stall's earnings to one of Nem'ro's subordinates, delivered at the crime lord's palace. When working at his stall, he was seen wearing light brown armor and carrying a backpack. Yerk's physical appearance included black hair, complemented by a moustache, along with blue eyes and a tanned complexion.
Yerk's initial appearance was in the video game Star Wars: The Old Republic, which was launched by BioWare in 2011. He is featured as a vendor selling specialist items on Nal Hutta, the initial planet for players choosing the bounty hunter or Imperial Agent classes. Instead of the standard credits, the prices for Yerk's goods were in Nal Hutta commendations, a unique form of currency acquired through rare drops from defeated enemies or as a reward for completing quests. He was subsequently removed from the game with the arrival of update 6.2 in Star Wars: The Old Republic: Onslaught. Later, he was added back into the game through update 7.1 in Star Wars: The Old Republic: Legacy of the Sith.