In the books
In Vidia and the Fairy Crown Dupe had made the replica crowns, Nora had found the real crown but thought it was just a fake to. So he, Vidia, Nora, and Prilla look through all the crowns until they had found the real one. Later, he and the others spoke at Vidia's hearing to clear her name. Vidia is dissapointed to her that Dupe copied the real crown completely. Crestfallen, Vidia's about to leave when Dupe remembers that the real crown will change its size to whoever is wearing it upon the magic words.
- His name appears to be short for duplicate, which means "a perfect copy" or "to create a perfect copy." This may suggest that Dupe's specialty lies in creating perfect replicas.