The Legend of William Tell - Season 1 Episode 8 Swarm

The Princess Vara has fallen ill. The band is taken in by Harana, a healer and leader of a group that calls itself the Watchers... Tucked away in a bountiful valley that does not appear on any map, the Watchers exist in a pocket of peace and plenty that the battle-weary heroes find difficult to credit can still exist in Kale. Stranger still, Harana and her followers have never heard of Xax and Kreel ... To Xax's exasperation, Kreel is toying with abandoning force as a method to subjugate the peoples of Kale - it is far too inefficient. Harana is the unwitting testing-ground for his new experiment. All Watchers must undergo a rite of passage in the so-called Chamber of Good Thoughts - where they are brainwashed and tortured in the name of the Master, who is really Kreel in disguise. The victims are taught to send out psychic shockwaves whenever Xax and Kreel are criticised. Kreel's plan is to send Harana's converts out as Ambassadors of Good Will - subtly undermining any resistance to a