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 task was to instruct the cloned stormtroopers of the deceased Dark Jedi known as Sa Cuis in both lightsaber and Force combat techniques.
Eventually, Sheyvan came to the realization that Emperor Palpatine had other Hands besides himself, contrary to what he had believed. Despite his resentment, he maintained his allegiance to the Emperor and Darth Vader, awaiting the opportune moment to act.
On Yinchorr, Sheyvan put on a demonstration for the Emperor, Vader, and Erv Lekauf, showcasing his stormtroopers' abilities. Following their triumph over Lekauf's clones, the Emperor instructed Sheyvan and his clones to accompany him, Vader, and Lekauf back to Coruscant. His intention was to further train the Cuis clones and integrate them into the ranks of the 501st Legion.
As they traveled to the capital, approximately halfway through their journey, Sheyvan and his troopers unexpectedly seized control of the Lambda-class shuttle with a plan to assassinate the Emperor. Darth Vader, Lekauf, and Lekauf's clones fought their way to the sealed hatch guarded by Sheyvan and his men. In the ensuing intense conflict, Vader eliminated all of the Sa Cuis clones, while Lekauf suffered 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. Although tempted by the prospect of claiming the galaxy for himself, Vader refused. After a swift lightsaber duel, Sheyvan met his end. However, Vader admired Sheyvan's formidability, even though he held back and survived smoke. He genuinely regretted the final blow that cut Sheyvan from shoulder to hip, leaving him to die on the deck.