Darth Stryfe was a Human male and a member of the One Sith Order led by Darth Krayt, a Dark Lord of the Sith. Eventually rising to the rank of Sith Lord, Stryfe served Krayt after the deposing of Emperor Roan Fel at the end of the Sith-Imperial War.
In the time of the ensuing conflict, he was selected to be Krayt's Fist, the head of the Empire's military. In 137 ABY, Stryfe oversaw a search for Jedi in the academy on the planet Ossus, and ordered its destruction. In that same year, after Krayt's Hands, Darth Nihl and Darth Talon, let former Jedi Cade Skywalker—who Krayt sought for his healing ability—escape the Sith Temple on the galactic capital of Coruscant, Stryfe was named Krayt's new Hand to replace Nihl.
The Sith discovered that Skywalker and his companions had attacked an Imperial outpost on the Deep Core world of Had Abbadon, and that among them was the spirit of the ancient Sith Lord Karness Muur. After Muur requested a meeting with Krayt, Stryfe was among those Krayt took with him to Had Abbadon. Discovering they had walked into a trap, the Sith engaged Skywalker and his allies. The Sith were defeated and Stryfe's body was recovered by Krayt's most trusted advisor Darth Wyyrlok III, who placed the Human Sith Lord in a bacta tank. Unbeknownst to Stryfe, Wyyrlok had killed Krayt after the battle, deciding that the Dark Lord needed to die in order for Krayt's vision of the Sith to live. Taken to the Sith Temple on the Sith homeworld of Korriban for further healing, Stryfe awoke to discover he could no longer feel Lord Krayt in his mind, and was convinced his master was dead. However, Wyyrlok convinced Stryfe that Krayt still lived, and explained that he would be taking control of the Empire while their Lord recovered. Believing the deception, Stryfe swore he would give his support to the Chagrian Sith Lord. Together, Stryfe and Wyyrlok left for Coruscant to secure the throne and implement the next stage in Krayt's plan for a unified galaxy.
After Darth Wyyrlok ordered the execution of the Final Protocol, a plan that saw the oceans of the Mon Calamari homeworld Dac poisoned and all of the inhabitants executed for their support of the commander of the Galactic Alliance Remnant, Admiral Gar Stazi, Stryfe was tasked with overseeing the Sith Empire's Outer Rim Third Fleet for the mission. During Stazi's operation to rescue the inhabitants of Dac, the Third Fleet engaged the Alliance fleet, aiming to ensure the evacuation attempts failed. However, after a fleet from Roan Fel's Empire-in-exile arrived to aid Stazi's forces, Stryfe was forced to withdraw. Following the events at Dac, it was revealed that Darth Krayt was alive. The Dark Lord of the Sith traveled to Coruscant and killed his betrayer Darth Wyyrlok, retaking his place as the leader of the Sith Empire. Darth Stryfe pledged himself to Lord Krayt and once again served at his side.
Afterwards, Darth Stryfe was one of the Sith who led an attack on the Hidden Temple on Taivas. The Sith, their loyal Imperials, and their new Sith Troopers were successful in winning the battle, But Cade Skywalker and his allies escaped the remains of the temple taking one of the Sith Troopers alive for answers.
Later on Coruscant, Darth Stryfe and his other Sith allies were attacked by the Empire-in-Exile and their Jedi allies. He and other Sith warriors joined the fray. Stryfe came face-to-face with Jedi Master Wolf Sazen, and they charged at each other, only to have struck each other down. Stryfe collapsed to the floor as Sazen become one with the Force.