In the books, the Nome King had a magic belt. The was reflected in the original script the Nome King had a magic belt made out of the Ruby Slippers; when he died it was going to turn back to the Slippers.
Word of Dante: Some synopses of the film falsely say Mombi was the sister of the Wicked Witch of the West. In the Ruth Plumly Thompson Oz books Mombi was actually the former Wicked Witch of the North before being overthrown by the Good Witch of the North. In The Marvelous Land of Oz, Mombi was a minor witch, who momentarily developed delusions of grandeur.