The Quell toxin was a poison that was developed from Quesh venom by the Sith Lord Drowl by the time of the Cold War. It was a new experimental toxin that was created for use by the Sith Empire where its intended use was controlling slave populations. Through small dosages into a water supply, infected subjects faced long drawn out periods of agony though an adjusted amount was capable of killing targets.
In the Cold War, a enslaved individual rebellion started on the Sith world of Dromund Kaas. The slaves being armed and resisting Imperial rule saw Lord Drowl assigned to handle the uprising. As a result, he was assigned Sergeant Slarin to serve as his assistant in the creation of a new prototype toxin that became known as Quell. However, it had not been tested at the time and Drowl tasked an Imperial spacer with its deployment in the slaves water supply to see its effects.
However, unknown to Drowl, Slarin had grown disgusted with the Sith Lord's appetite for causing the suffering in living beings. He believed that the quick death of the slaves would help promote his stagnant career and tried to convince the spacer to use a modified dosage of the toxin to quickly kill the rebels.
The toxin features in the quest "Testing Grounds" where the player has the dark side option of choosing Drowl's option of deploying the toxin or the light side from Slarin to adjust the poison to immediately kill the slaves.
The toxin features in the quest "Testing Grounds" where the player has the dark side option of choosing Drowl's option of deploying the toxin or the light side from Slarin to adjust the poison to immediately kill the slaves.