Ozma

"'...Although she was so young and inexperienced, she ruled her people with wisdom and Justice.' - L. Frank Baum, The Marvelous Land of Oz"

Summary
Ozma is one of the newest members of the Congregation. Not much is known about them at this time, though they have repeatedly made references to being "lost" in some capacity.

During Star's arrival on Earth, they were the last one to arrive. It was then discovered that they were actually an animate illustration. Umbra told them of their fictional nature - as they had not been privy to it previously - and they subsequently fled.

Later, the Red Right Hand managed to return them to their rightful place as an illustration in The Marvelous Land of Oz. Before that, Ozma had commented that remaining in the real world had begun to make them fade away.

Presumably, that would be bad.