Keeper Agruss

Keeper Agruss was a sadistic and despicable overseer of slaves owned by the Zygerrian Empire, and stood out even in a culture of slavers.

History
Keepr Agruss first appeared in the fourth season of Star Wars: The Clone Wars as a Zygerrian in charge of overseeing a large number of Togruta slaves recently captured by the Zygerrians.

When a captured Obi-Wan Kenobi and Captain Rex are delivered to the prison Agruss is in charge of, he personally and gleefully murders almost a dozen Togruta slaves to show Obi-Wan what will happen if he attempts to defy him or cause any trouble.

His next appearance sees him brutally abusing his position, a sentiment shared by the Zygerrians working under him. They take perverse joy in tormenting Obi-Wan and the Togruta slaves and forcing Obi-Wan to be subservient to them. When the Republic army arrives to liberate the slaves, Agruss decides that if he can't have his slaves no one can and attempts to destroy the entire complex, simply out of spite.

After doing this he gloats that a Jedi like Obi-Wan would never kill an unarmed man. Undeterred, Obi-Wan steps aside to let Captain Rex hurl an electrified javelin into Agruss' chest, killing him. His hover-chair then crashes into a nearby computer screen, plunging his face right into it.

Trivia

 * Agruss' villainy was such that he is explicitly shown in a commercial for the Complete Fourth Season of the Clone Wars as a character who deserved to die.