In 3643 BBY, the final year of the Cold War, Nelex was assigned to work with Jedi Master Cin Tykan and his Padawan Aris Vauranelle on the planet Taris, which was ravaged by the Sith Lord Darth Malak three hundred years ago. When Master Tykan departed with a research expedition to take pollution readings and displayed no signs of the rakghoul plague, Nelex tried to contact him, but there was no reply. Furious to learn that Tykan had caused the deaths of many of his workers, Nelex requested that the Jedi Knight assigned to bring Tykan back to the base kill the Jedi Master. When Tykan raided the Republic base and abducted his Padawan, Nelex held the line and fought off rakghouls alongside his men but was unable to stop the Kaleesh Jedi. When the Jedi Knight returned with word that Tykan had been cured and was headed back to Tython for rehabilitation, Nelex was furious that the Jedi had protected their own before taking into account the justice the dead deserved.
Despite being a Republic soldier, Nelex firmly believed in killing someone for their crimes. He repeatedly tried to convince the Jedi Knight to kill Tykan for attacking the soldiers he led, and was furious when the consular spared their fellow Jedi.
- Star Wars: The Old Republic (First appearance)