Sheyvan, a Human male strong in the Force, operated as an assassin. During the early years of the Galactic Empire, he held the position of one of the Emperor's Hands. His assignment involved instructing the cloned stormtroopers created from the deceased Dark Jedi known as Sa Cuis in both lightsaber and Force based combat techniques.
Eventually, Sheyvan came to the realization that Emperor Palpatine had multiple Hands, contrary to what he initially believed. This revelation caused him bitterness, but he maintained his loyalty to the Emperor and Darth Vader, waiting for an opportune moment to act.
On Yinchorr, Sheyvan presented a demonstration of his stormtroopers' abilities to the Emperor, Vader, and Erv Lekauf. Following their successful performance against Lekauf's clones, the Emperor commanded Sheyvan and his clones to accompany him, Vader, and Lekauf back to Coruscant. His intention was to provide further training to the Cuis clones and integrate them into the ranks of the 501st Legion.
Midway through their journey to the capital, Sheyvan and his troopers abruptly seized control of the Lambda-class shuttle with the intention of assassinating the Emperor. Darth Vader, Lekauf, and Lekauf's clones fought their way to the sealed hatch where Sheyvan and his men were located. In the ensuing intense confrontation, Vader eliminated all of the Sa Cuis clones, while Lekauf sustained severe burn injuries from a flamethrower. Sheyvan revealed to Vader that the Emperor was exploiting everyone and urged him to join in overthrowing the elder Sith Lord. Despite being tempted by the prospect of claiming the galaxy for himself, Vader refused and, after a brief lightsaber duel, killed Sheyvan. Vader admired Sheyvan's formidable fighting skills, even though he held back some of his power and survived the smoke. He regretted the final blow that cut Sheyvan from shoulder to hip, leaving him to die on the deck.