During the era of the Cold War between the Galactic Republic and the Sith Empire, a Trandoshan male warlord named Kephess rose to prominence as a fearsome mercenary leader. He commanded the notorious mercenary group known as the Warstalkers. Due to a shortage of troops, the Republic military contracted the Warstalkers to secure the planet Denova, crucial for its Baradium supply, and to resist the encroaching Sith Empire's invasion. In a fierce confrontation with Imperial forces, Kephess sustained mortal wounds, but his life took an unexpected turn when the Dread Masters, then fugitives from the Empire, intervened. They imbued Kephess with a portion of their immense power, resulting in his miraculous recovery and granting him abilities far exceeding those of ordinary Trandoshans. The Dread Masters chose Kephess as their "chosen one," intending for him to be their instrument of terror and chaos throughout the Galaxy.
Kephess' Warstalkers betrayed the Galactic Republic and sided with the Imperial forces on Denova, who were also under the Dread Masters' influence. Kephess, declaring himself the ruler of Denova, initiated a war against both the Republic and the Sith Empire. Denova became a battleground for a three-sided conflict involving the Republic, Imperial loyalists, and the corrupted forces of the Dread Masters. Both galactic superpowers dispatched strike teams to eliminate the rogue warlord. After numerous battles against Kephess' subordinates and minions (including Zorn, Toth and Colonel Vorgath), they finally succeeded in ending the Trandoshan's reign of terror. Despite piloting an advanced Imperial battlewalker, Kephess was defeated within his own stronghold. However, the Dread Masters once again intervened, rescuing the renegade Trandoshan and vowing revenge on those who ended his rule on Denova.
Despite his previous defeat on Denova, Kephess resurfaced on the planet of Asation later. The Dread Masters, aiming to summon the ancient Gree threat known as the Terror From Beyond, resurrected Kephess and transformed him into the Undying. They augmented his size and strength, implanted high-tech armor onto his body, and imparted more knowledge of their Force powers. Kephess subsequently led the Dread Masters' forces on Asation, where he manipulated the hypergate intended to summon the Terror From Beyond. However, heroes from both the Sith Empire and Galactic Republic deployed strike teams of eight or sixteen to neutralize the threat. After three battles, these heroes confronted Kephess the Undying, ultimately defeating him once more, presumably by the same team that had saved Denova. In a bizarre turn of events, Kephess was pulled into the hypergate by a tentacle belonging to the Terror From Beyond.
Kephess serves as a key antagonist and the final boss that players must overcome in the Operation missions Explosive Conflict and Terror From Beyond featured in the 2011 video game Star Wars: The Old Republic.