Thexan was a Force-sensitive human male who served the Eternal Empire. He was the son of Emperor Valkorion and Senya Tirall, and fought many battles on the Eternal Empire's behalf. He died in a brief lightsaber duel with his twin brother, Arcann.
Thexan as a child
Thexan was the son of Emperor Valkorion of the Eternal Empire and Senya Tirall, one of the Knights of Zakuul. He and his twin brother Arcann were trained from childhood to be warriors, with Thexan always being there in harsh times. The twins and their younger sister, Vaylin, ignored their mother, but their father ignored them as well when they were children. Arcann grew more resentful towards their father, despite Thexan's attempts to placate him.
When Vaylin's growing power and mental instability forced Valkorion to send her to Nathema to control her power, Thexan would make regular visits to her; he resented the planet being a void in the Force as much as his sister did.
Eventually, when the children reached adulthood, Arcann retrieved Vaylin from Nathema. Valkorion then presented Vaylin with her first lightsaber. The twins move to defend when their sister ignited her blade, only to stay their hand at their father's command. Vaylin soon deactivated the blade and pledged her allegiance to Valkorion.
Thexan looks after his brother's injuries on Korriban.
By 3636 BBY, Arcann and Thexan requested their father's permission to lead an attack to test the strength of the galactic powers of the greater galaxy. They fought on many worlds, driving back the Galactic Republic and the reconstituted Sith Empire. At some point during the conquest, Arcann and Thexan led an assault on Balmorra before finally striking at the Sith world of Korriban. During the attack on Korriban Arcann lost his arm and received heavy scarring to his face, while Thexan was by his brother's side after the injury. Soon after the attack on Korriban, Thexan was to report to his father on the status of the invasion.
Arcann and Thexan later presented the lightsabers of fallen Jedi and Sith as trophies from the battle to their father, with Valkorion turning away in silence, infuriating Arcann, and overcome by the dark side of the Force he attempted to attack the Emperor. Thexan pulled his brother back. Arcann turned his attention to his brother and struck out at him, but their brief duel ended when Thexan was struck down by his brother with a cut across the stomach, killing him. Coming to his senses, Arcann cradled his twin's body in his arms before looking up to see Valkorion looming over him, asking his remaining son to come with him.
Thexan and Tenebrae, the true face of his father.
A funeral was later held saying that he was killed in the Core Worlds. The truth of his death remained unknown to everyone, including Senya, for five years, until Vaylin told her the truth during the Battle of Asylum.
Years after his death, Thexan would join his family and everyone else ever wronged by Valkorion in purging the ancient entity's last remaining vestige. He also forgave his brother for his past mistakes.
Thexan first appeared in Sacrifice, a cinematic trailer produced by Blur Studio for Star Wars: The Old Republics fifth digital expansion, Knights of the Fallen Empire. The trailer was released at the Electronic Eterntainment Expo on June 15, in 2015. While not named in dialogue, Thexan's name can be seen in Aurebesh on his crib at the beginning of the trailer. He is voiced by Erik Todd Dellums who also voiced his twin brother Arcann.