Fostel

 was a Bishop of the Church of the Maker on Sarath. On the encouragement of Zeckler, he abducted and attempted to question Susan Foreman about her religious beliefs, subsequently condemning her to a 'trial by water' in a swimming pool when they were not satisfied with her answers. When Susan was rescued by Ben Lant, the Doctor and Ian Chesterton, Fostel was killed when he fell into the pool during the fight after the lights were turned off and drowned in his heavy robes before anyone realised what had happened. (PROSE: City at World's End)