The Quell

The Quell (not the Quail) is the oppositional force of Sylvain, which balances her power. It was the primary antagonist of most of the final arc of Amnesty.

Forms
"The Quell" refers to three different existences/forms:
 * The "Heart of the Quell", the enormous ("cosmic horror big") perfect red sphere that comprises its central physical form and is said to exude light and anger
 * Its clouds, which pervade many areas and infect those which enter them with the mind of the Quell
 * Its mind, which acts as a hivemind and is present in/around the Heart as well as in every being infected by it

Motivation
While Thacker was under the control of the Quell, he told Aubrey that it was attempting to revitalize the Heart of Sylvain above all else, even at the cost of the lives of the planet's inhabitants. However, in Episode 35, Aubrey entered its mind (and it hers) and detected that when Aubrey mentioned herself as Sylvain it triggered a flash of sadness within its otherwise pure unadulterated hatred. It also subsequently told Duck "I need no reason to destroy. I am destruction." This heavily suggests that it may have realized that the Heart of Sylvain was no longer present within the planet and continued destroying everything in anger.

Powers

 * Infection: The Quell can overtake beings who enter its clouds. The Quell seems to be able to reformat the mindset of anything it "infects" and inoculate them into its hivemind.
 * A deeper and more powerful form of this power is seen in Episode 35 in the chamber of the Heart of the Quell, where it maintains the life of countless floating islands as well as manipulates the movement of their flora to its will.
 * Telekinesis: The Quell is also seen being able to control the motion of the islands in its chamber, enough to cause a collision between two of them strong enough to entirely destroy both. This power is certainly linked to its infection, as it is not shown to be able to use telekinesis on Aubrey, Duck, or Thacker.