Ropemaker, book 2: Angel Isle
Peter Dickinson2006

'They are terrible. They are like the demons of old. They must be stopped, and you are here to bring that about, where everyone else has failed. You must find the Ropemaker.' Despite his immense powers, the Ropemaker alone could not control the chaos raging through the Empire, so he chose twenty-four magicians to aid him in his task - the Watchers. They pledged to use their magic only to protect the people but the promise that bound them has now corrupted them. They have become a single, terrible entity with a limitless desire for domination. Only the Ropemaker may be able to stop them, but he has not been seen for over two hundred years. Into this dangerous world come Saranja, Maja and Ribek. They too are seeking the Ropemaker so that he might restore the ancient magic that protects their Valley. It is the task they were born to, but now it seems they have a greater purpose with far more at stake should they fail.