A male Twi'lek of the Lethan variety named Tre Sana resided on the planet of Kalimahr within the Tython system. This was during the apex of the Infinite Empire's dominance, a fact unknown to Sana and the other inhabitants of the system. Sana, a criminal and a renegade, was an ostracized figure. His physical form had been altered through alchemy by Je'daii Master Dam-Powl to transform him into an informant. Around 25,793 BBY, Sana acquired information about the schemes of the Stargazers. He then alerted the Je'daii and aided them in their mission to locate and neutralize the threat.
Tre Sana, a red-skinned individual from the Twi'lek population of Kalimahr, was born with an unusual physical trait: an extra lekku growing from the back of his head. This made him an oddity among his fellow Twi'leks. Due to being shunned and tormented for this extra brain-tail, Sana turned to crime to survive. At the age of seventeen, he committed his first murder outside of a bar. Over the following years, Sana gathered a substantial following, and his gang relocated their operations to the planet of Shikaakwa. There, his once-significant operation became just another gang amidst the planet's pervasive corruption. The Nine Houses eventually dismantled his criminal enterprise, but they spared his life, recognizing his potential as a spy. Two of these houses employed him as a messenger, tasking him with delivering sensitive messages that could not be written or transmitted electronically, requiring him to deliver them in person. During this period, he crossed paths with Dam-Powl, a Cathar Je'daii Master, who utilized a mystical form of alchemy on Sana's mind, rendering it impenetrable, even to a Je'daii, to ensure his survival. In return for this mental alteration, Sana was promised wealth and a new identity if he agreed to serve as an occasional informant for the Je'daii Order.
In 25,793 BBY, Sana contacted Master Dam-Powl regarding rumors of a group known as the Stargazers and their desire to leave the Tython system. He then met with Lanoree Brock, a Je'daii Ranger, on Kalimahr and pledged to assist her in locating her brother, Dalien Brock, the leader of the Stargazers. Sana brought her to Kara, a corpulent socialite in the city of Rhol Yan, and helped the Je'daii escape her apartment after stunning the obese woman. They then leaped from her skyscraper, landing on Brock's Peacemaker cruiser and setting course for the planet Nox. Despite maintaining a degree of emotional distance, Sana and Brock developed a certain camaraderie as they faced the dangers of Greenwood Station together in their search for the crime boss Maxhagan and the hidden labs of Pan Deep. After gaining access to the concealed labs beneath the city, Sana sustained injuries when the Stargazers captured them and brought them before Dalien Brock. Left for dead after they completed the Gree technology being constructed there, Sana and Brock escaped to find the domed city of Greenwood Station under attack by rival stations. While fleeing across the toxic wastes outside the city, Sana became seriously ill from the contaminated atmosphere and was confined to the Peacemaker during their voyage to the planet Sunspot.
While resting aboard the ship on Sunspot, as Brock searched for her brother, Sana grew suspicious when the Stargazer ship departed and Brock did not return from the mines. He took the droid Ironholgs with him, and they discovered Brock severely wounded in the mines with a blaster wound in her chest inflicted by her brother. He carried her back to the ship, where Brock used her knowledge of Force alchemy, specifically Alchemy of flesh, to merge a living piece of her own flesh, an experiment of hers, into the blaster wound, healing herself. Still recovering from the atmospheric exposure on Nox, Sana accompanied Brock to Tython as she attempted to intercept her brother and the Stargazers. They pursued him into the Old City, entering without backup from the Je'daii due to the violent Force storms plaguing the world. They avoided traps set by the Je'daii at every turn, but were eventually ambushed by a Stargazer who fired a series of blaster shots at Brock. Sana, yelling for her to move, pushed Brock aside and took a blaster bolt to the neck, rendering him comatose. Brock left Sana in the tunnel for several hours while she hunted her brother. After finding and killing him, she returned to care for Sana's injuries. She transported him to the Temple of Science, Anil Kesh, where healers with superior skills to Brock's tended to him.