The Rodian male who fathered Yonak held the position of crime lord for the Son-tuul Pride criminal organization. He maintained this role until the initial assault on the Son-tuul Pride which occurred in 0 ABY. Following the demise of his father, Yonak assumed leadership of the Pride.
Prior to 0 BBY, Yonak's father reigned as the head of the Son-tuul Pride, a criminal syndicate that had been causing havoc in the Outer Rim Territories for numerous years. In that specific year, the Galactic Empire initiated a crackdown on smugglers working for the Son-tuul Pride. Yonak's father responded by decapitating those smugglers who used this crackdown as an excuse for failed deliveries, storing their heads in a vault to feed his creature.
When a Twi'lek smuggler returned to Yonak's father to explain his lost cargo, the rodian threatened him. Yonak's father demonstrated what had happened to other unfortunate smugglers and prepared to kill him. However, he found a tracker on the smuggler. At that moment, the Empire arrived. Led by Darth Vader, a group of stormtroopers stormed the Son-tuul Pride base. Yonak's father sought refuge and unleashed his beast upon the Imperials. While the creature occupied Vader, the Rodian lunged at him with his dagger. Vader used the Force to seize him and then fed him to the beast.