Which NON Disney characters would you include in Descendants?

If you could add characters from other non-Disney stories or characters that have not been adapted by Disney or in the Descendants universe, who would they be and how would you integrate them?

For example, I would include Little Red Riding Hood, but not Little Red Riding Hood's daughter, niece or sister, but the original Little Red Riding Hood. She would not be from the United States of Auradon, but would come from a distant kingdom that is not part of the union of kingdoms. She would come to Auradon thanks to a scholarship granted by Kings Ben and Mal to study at the Auradon high school.

What other characters would you add? How would you adapt their stories to the world of Descendants? Let me read your ideas!