The Quell toxin emerged as a poison concocted from Quesh venom by the Sith Lord known as Drowl during the era of the Cold War. This novel experimental toxin was designed for the Sith Empire, specifically to manage slave communities. Administered in small quantities via water sources, it subjected victims to prolonged suffering, though a higher concentration could prove lethal.
During the Cold War period, a enslaved individual rebellion erupted on the Sith planet of Dromund Kaas. With slaves armed and defying Imperial authority, Lord Drowl was tasked with suppressing the revolt. Consequently, Sergeant Slarin was assigned to aid him in developing a new experimental toxin, which was subsequently named Quell. Lacking prior testing, Drowl instructed an Imperial spacer to introduce it into the slaves' water supply to observe its effects.
Unbeknownst to Drowl, Slarin had grown repulsed by the Sith Lord's insatiable desire to inflict agony on living beings. He thought a swift demise for the slaves would help boost his stalled career and urged the spacer to administer a modified dose of the toxin, ensuring a rapid death for the rebels.