Muse

"They came to be at the dawn of the universe as beings of pure energy. The Muses see all stories and all outcomes at all times. They do not see the world world like you and I."

Muses are called Dreaming Stars by Ozites. As Adora, Neutral Witch of the West explained to Emma Crewe:

'They existed to shape the Universe and its stories. They created countless worlds and inspired stories to spark life on them. Due to their nature, Muses break apart on their travels. Pieces of their power are left behind on various worlds, allowing gods, sorcerers and fairies to transform and adapt the pure energy to their bodies. This is how magic was created. They are where all magic originated. They are where magic returns to when its owners die."

Ozma: A Muse We Know
Calliope is the last, living Muse to survive the war with the Shadows. She is currently living as Ozma of Oz. Although she was described as 'the smallest of them' she still had the considerable powers and abilities to create the world of Oz and rest there. Her son Orpheus claims to be merely human, but has a staggering array of powers himself.

A Muse's body parts are coveted for their power, and used to craft weapons or specific tools.