During the Cold War era, Diago Hixan was a Human male crime lord operating on the planet of Tatooine. He was a bitter enemy of Nok Drayen until the latter's supposed demise. His life came to an end when he was killed during a confrontation that involved the Jedi Nariel Pridence, the Sith Vaverone Zare, and the smuggler who would eventually be known as the Voidhound.
In the time before the signing of the Treaty of Coruscant, Diago Hixan was locked in a power struggle with the crime boss Nok Drayen for control of the galactic criminal network. They spent many years engaging in daring heists, treasure hunts, and conflicts across numerous worlds. Shassa Dalle became a source of contention between the two. Much to Hixan's frustration, Drayen managed to "steal" her away. For years, Hixan made fervent attempts to win her back from Drayen, but these efforts ceased after he inadvertently caused Shassa's death. Following Nok Drayen's apparent death, Hixan declared himself the victor, bringing many criminals throughout the galaxy under his control.
In the year 3643 BBY, a smuggler captain journeyed to Tatooine seeking to acquire a sensor computer from Diago, intending to use it to locate Nok's lost treasure. The smuggler reached out to Diago's lieutenant, Tookreek, to set up a meeting with Diago, promising recognition for finding the treasure in return. However, a Sith by the name of Vaverone Zare also desired an audience with Diago, primarily to obtain the holocron of Darth Nihilus that he possessed, and had initiated attacks on his holdings to garner his attention. The Sith's activities drew the attention of the Jedi Knight Nariel Pridence.
When all the interested parties converged at Diago's hideout located in the Lightspring, Diago refused to listen to any of them. Simultaneously, the smuggler's companion, Risha contacted them via holo to inquire about her partner's progress. Diago was immediately captivated by her, demanding that he meet her. Zare interrupted, trying to convince him to assist her in killing Nariel, but he refused to listen. Zare then attempted to use a mind trick on the smuggler to turn against the Jedi, but the smuggler proved too strong-willed for it to work. Adding to the chaos, Diago inexplicably ordered his droids to attack everyone present. In the ensuing conflict, Diago met his end, along with Zare.