Bornan Thul was a male Human who formerly held the position of noble on Alderaan. He co-owned Bornaryn Trading, was the older sibling of Tyko Thul, married to Aryn Dro Thul, and the father of Raynar Thul.
Around 10 BBY, Bornan Thul's path first crossed with that of Han Solo on Alderaan. At that time, Solo, using the name Vykk Draygo, was employed as a pilot by the priests of Ylesia. After his ship sustained damage from a pirate attack, Solo landed on Alderaan for repairs. During this stopover, he encountered Thul, along with Aryn Dro, who was Thul's girlfriend at the time, in a college cafe. Thul developed a dislike for Solo when he flirted with Aryn, recounting his escape from the pirates. Anxiously, Thul quickly departed the cafe with Aryn, preventing Solo from pursuing his advances further.
Bornan had come into possession of a navicomputer, tasked with delivering it to Diversity Alliance leader Nolaa Tarkona at a trade conference. However, he uncovered the navicomputer's secret: the location of a warehouse containing a plague. Horrified by this discovery, he went into hiding, prompting Tarkona to hire bounty hunters to locate him.
For several months, Bornan evaded capture, eventually visiting the plague warehouse with the goal of destroying it. Unfortunately, he lacked sufficient ammunition and was forced to retreat. On his return journey, he was ambushed by bounty hunters, resulting in damage to his ship.
After being rescued by Zekk, Bornan revealed that Boba Fett (actually Ailyn Vel using her father's identity) had hacked into his ship's navicomputer and obtained the coordinates of the plague warehouse.
Following the recording of an encrypted message to his wife explaining their plan, Bornan, Raynar, Zekk, Jacen and Jaina Solo, Tenel Ka, and Lowbacca gathered explosives and proceeded to the warehouse with the intention of destroying it. As they neared the completion of the wiring, Diversity Alliance ships appeared. During the subsequent confrontation with Tarkona inside the warehouse, several plague canisters were ruptured, releasing viruses, including a disease specifically targeting Humans.
Infected by the virus, Bornan isolated himself in a sealed room to prevent the plague's spread. He prevented IG-88, programmed to protect Bornan, from breaking down the door and instructed him to protect his son. Expressing his pride to Raynar, Bornan ordered his son, the droid, and Zekk to escape the asteroid and complete his unfinished task: the destruction of the storehouse and the deadly biological weapons contained within.