Darth Atrius, a male Sith Lord, existed during an era when the Sith's influence and numbers were substantial. He was known for wielding two distinct crossguard lightsabers. Following the Battle of Yavin, the smuggler known as Sana Starros came into possession of his pair of crossguard lightsabers. She subsequently sold one to a crime lord residing on Hradreek and the other to the forces of the Galactic Empire. Both were ultimately annihilated by Luke Skywalker together with Darth Vader.
Darth Atrius lived in an age where the Sith held considerable power and dominance across the galaxy. During his lifetime, he crafted a pair of crossguard lightsabers, employing them as his weapons in combat. Atrius utilized these sabers to defeat numerous adversaries and secure many victories. Over the course of time, Atrius's intense rage permeated the lightsabers, granting them the capability to awaken the inner fury of whoever wielded them, driving them into a killing rage. Eventually, Atrius died, but his sabers continued to exist.
Many years after his passing, Atrius's lightsabers were discovered by the smuggler Sana Starros, who had accepted a commission to retrieve the weapons for a crime lord situated on Hradreek. One of the lightsabers was successfully delivered to the crime lord, while Starros sold the other to the Galactic Empire under the instructions of Emperor Palpatine. In an attempt to deceive both parties, she provided one saber to each employer, hoping they would not notice the missing second saber. The Imperial officer who received one of the sabers was pleased with it, unaware that the Emperor was searching for the pair. Starros then gave the second saber to the crime boss, but was exposed for her deception.
The crime boss activated the blade and started questioning the smuggler about the location of the other saber, succumbing to a frenzy and slaughtering all of his men. The Imperial officer presented the saber to Darth Vader, who intended to give the sabers to his Master, Darth Sidious. Upon learning of the missing saber, Vader executed the officer and began his search for the other. Meanwhile, the rebel pilot Luke Skywalker entered the room where the crime boss had killed his crew and discovered the lightsaber on the floor. He used the weapon to kill a squad of Imperial Stormtroopers who found him with the corpses. To avoid more Imperial forces, Skywalker stole a nearby podracer and fled, but crashed shortly after. Realizing he had evaded the Empire, Skywalker decided that the lightsaber was too dangerous to be kept in one piece, and used his lightsaber to destroy Atrius' blade.
Simultaneously, Vader encountered a group of thugs hired by Starros to deter the Imperials, using the weapon to eliminate them all. He proceeded to track Starros to a warehouse where she had set an ambush for him. Starros detonated the roof of the warehouse, crushing Vader and allowing her to escape. After escaping the rubble, Vader observed Skywalker leaving, and decided that the saber was too unpredictable, crushing it.
The first mention of Darth Atrius occurred in the fourth annual issue of the comic series Star Wars, penned by Cullen Bunn and released by Marvel Comics on May 23, 2018.