Diago Hixan was a male Human crime lord on the planet Tatooine during the Cold War. He was a sworn rival of Nok Drayen before his "death". He was killed in a confrontation with the Jedi Nariel Pridence, the Sith Vaverone Zare, and the smuggler who would later be known as the Voidhound.
Before the Treaty of Coruscant, Diago Hixan competed with the crime lord Nok Drayen to rule the galactic underworld. Over many years two scored bigger heists, hunted for treasures, and fought across many worlds. One point of contention between them was Shassa Dalle. To Hixan's dismay, she was "stolen" by his rival Nok Drayen. Hixan spent years making impassioned attempts to win her back from Drayen, but this ended ended after he accidentally caused Shassa's death. Following the apparent death of Nok Drayen, Hixan claimed victory. bringing many criminals throughout the galaxy under his heel.
In 3643 BBY, a smuggler captain came to Tatooine to acquire a sensor computer from Diago to assist in finding the lost treasure of Nok. The smuggler contacted Diago's lieutenant, Tookreek, to arrange a meeting with Diago in exchange for being known for finding the treasure. However, a Sith named Vaverone Zare was seeking a meeting with Diago too, mainly to acquire the holocron of Darth Nihilus he possessed, and had launched attacks on his holdings to get his attention. The Sith's activity brought the attention of the Jedi Knight Nariel Pridence.
When all parties arrived at Diago's hideout in the Lightspring, Diago refused hear any of them. At the same time, the smuggler's companion, Risha called via holo to check on her partner's progress. Diago quickly became englamoured with her, compelling her to sign off. He demanded that he meet her. Zare interrupted him, attempting to persuade him to help her kill Nariel but he would not hear her. Zare then attempted to use a mind trick on the smuggler to turn on the Jedi but the latter proved strong willed for it to work. To add to the madness, Diago irrationally ordered his droids to attack all present. In the ensuring fight, Diago was killed, along with Zare.
- Star Wars: The Old Republic Explorer's Guide