They are animals as a painter might idealize them: deer-like grazers with long, exact legs and smooth gold or silver coats, long-necked birds of pure white, and smaller things like hares or cats, each of its kind identical to every other. Their coats never tangle, their feathers never ruffle, their eyes are calm and large. What travellers remember is the movement. A herd of fifty turns as one body, every head lifting at the same moment, every hoof striking the ground together, so that their passage sounds like a single slow drumbeat in time with the plane’s hum. They make no other sound and have no smell.

They live in herds and flocks across the domed hills and along the exact rivers of the Apex, moving in long, perfect curves that never cross.

They do not hunt and are not hunted. They do not fight, mate, or rear young, and they do not seem to eat, though some graze. They move together in perfect synchronization, and when a traveller walks among them the herd parts and closes again without a single animal touching another or the traveller. They show no fear and no curiosity.

They never collide, never tire, and never die. A Harmony-Beast struck by a traveller is not hurt; the plane sets it right again.

They give nothing and take nothing. Their danger is only the unease they cause: a traveller who watches them too long begins, without meaning to, to walk in step.

Travellers' accounts of beasts that never die have fed tales of a paradise of animals on Caeldon, where nothing eats anything. Those who have seen them describe them less kindly, as a meadow full of clockwork.