|First appearance||"I Spit on Your Grave"|
|Last appearance||"I'm Your Daddy"|
Derf was a young Luxan in the employ of General Fin Sterikk. As the former general's right hand man, Derf accompanied Sterikk when he took a job to help prospective crime lord Esseret destroy her main rival on the moon of Egrof. He and Sterikk quickly discovered that another Luxan had already arrived at the moon and had been posing as the general. Sterikk agreed to do the job for which Esseret had hired him, but also vowed to kill his impostor, much to Derf's delight. When Sterikk learned that the impostor was Ka D'Argo, a former soldier under his command who had sacrificed himself to protect the general, Sterikk was reluctant to carry out his vow. D'Argo, feeling that Sterikk's decision to aid Esseret was not honorable for such a decorated warrior, challenged Sterikk to a fight to the death. Derf accompanied Sterikk to the fight and witnessed him face off against D'Argo, though Derf was confused that Sterikk chose to use his Qualta blade against D'Argo as Sterikk had earlier promised to use his pulse pistol against the "impostor". As the two Luxans squared off, Derf shouted encouragement to Sterikk while Jool did the same for D'Argo. Soon, D'Argo mortally wounded Sterikk and Derf ran to the former general's side, clearly unhappy to see his superior die. Sterikk, as he often did, told Derf to show up and do something useful for once. Derf took his general's final order, volunteering to remain on Egrof to make sure Esseret and her former rival Kitrap worked together to get the moon's industry working again to produce orujna. He promised D'Argo he would report to him if either party did not follow through on the terms.
Derf was rather loyal and subservient to Sterikk, frequently agreeing with the former general and clearly admiring him. In spite of, or perhaps because of his enthusiasm for Sterikk, the older Luxan found Derf to be an annoyance, constantly telling him to shut up, an order Derf always tried to obey. Even in Sterikk's dying breath, when he angrily told Derf to do something useful for once, Derf admitted that he would miss the general and his constant orders for Derf to cease talking.
- Sterikk: Shut up, Derf.
- Derf: Shutting up now commencing, sir.
- Derf (about Sterikk): My only regret is I'll miss him telling me to shut up.