Mombi
Mombi is a wicked witch who once conquered and ruled the Gillikin Country. She enslaved Ozma's father and grandfather, and then teamed up with the other Wicked Witches of the East, West, and South to conquer and divide the land of Oz. After being forced to disenchant Princess Ozma, Mombi was stripped of her magic powers and never appeared in L. Frank Baum's books again. However, in Ruth Plumly Thompson's The Lost King of Oz, Mombi returns and is killed by being doused with water.