Thorn was once a Jedi Knight, trapped in an ancient ghost ship with his master and his lover. Together with an Ithorian scientist, they found the Korendums. Thorn was the only one to understand the potential of those antique crystals, and fell to the dark side. He murdered his master before taking the Korendums with Yele and Suunfuus and used his new powers to convince the artificial intelligence of the Gorgorror to let them flee. Not long after their escape, Thorn tried to steal the crystals from his companions.
In reaction, Yele brutally broke up with him, and the three went their separate ways. While Thorn joined the Empire as a Dark Jedi and soon became "Lord Thorn," Yele went to Taypho and Suunfuus to Oriadann, taking their respective crystals far from him. However, the fallen Jedi never abandoned the hope of using the power of the Korendums for himself. He undertook the installation of a superlaser similar to that of the first Death Star on his own Super Star Destroyer, augmented by the overwhelming power of the reunited crystals.
Sometime after the Battle of Yavin, Thorn located Yele through his spies. They followed some Rebel agents in a diplomatic mission on Taypho, and the Dark Jedi made considerable efforts to keep them alive and facilitate their travels, sending a patrol to "save" them from Jabba's men on Tatooine.
Later, he attacked Yele and the Taïs rebellion in order to retrieve the Korendum kept on Taypho. Though Yele and the Rebel operatives managed to flee, Thorn took the crystal and left the planet, only to head for the planet Brazadann.
On the basaltic planet, the Wardog of the Emperor contacted the local population in order to find Suunfuus and his Korendum, but they refused. He then led a terrestrial assault on the planet and besieged the massive fortress that served as a capital and as the only city of the planet. In the final battle of his campaign, Thorn led stormtroopers and Imperial Royal Guards through the defense and reached the central forge were the Korendum were kept.
Ultimately, his plans were thwarted by the same group of Rebel agents he used to locate Yele and Suunfuus, and he wasn't able to use the crystals for his superweapon.
He was an ambitious, rogue Jedi who let himself be corrupted by the dark side, attracted by the potential of the Korendums, crystals with great energy potential. Thorn killed his master and lied to his companions for the sole purpose of acquiring the crystals for his own goal. Unable to achieving it immediately, he submitted himself to the Empire and seemingly attained a high status in the Empire.
However, Thorn was patient enough to carry on his personal projects and aspired to built his own superweapon, tracking his old companions over the years.
Thorn was a skilled fighter and able practitioner of the Force, using Force powers such as telekinesis and Force Wound. Deeply immersed in the dark side of the Force, he was always shrouded in an aura of fear, consolidated by his colossal stature and deep, scarlet robes marked with the Imperial seal.
Daymon Thorn was created by Christophe Debien and Patrick Bousquet for the ambiguously canon roleplaying scenario "La Légende des Cristaux," which appeared in the French magazine Casus Belli 76.
The fate of Thorn is not stated in the story, as it is a roleplaying scenario with an open ending. One of the possible, mentioned conclusions anticipated his victory and his recovery of all the Korendum. However, the in-universe citation of Lyoon pointed toward a player victory, as the "Young Heroes just immortalized the Legend of the Crystals" and "the time of Balance had come."