Celeste is more on an entity now than a human being. she was an 18th century witch who was burned at the stake for practicing dark magic. She escaped by having her soul jump in to the body of one of the men executing her. This way she has been able to keep ahead of death for over two hundred years.Both Malleus Maleficarum and the Order of St George have been hunting her for centuries.
She causes chaos and ruin where ever she goes by teaching novice witches and wizards magic that is way over their head and stepping back and watching with maniacal glee what happens next. Her current form is said to be that of a beautiful red headed woman from California.