In the books
In Vidia and the Fairy Crown Dupe makes the replica crowns, and Nora finds the real crown but thinks it is just a fake too. So he, Vidia, Nora, and Prilla look through all the crowns until they find the real one. Later, he and the others speak at Vidia's hearing to clear her name. Vidia is disappointed that Dupe copied the real crown completely. Crestfallen, Vidia is about to leave when Dupe remembers that the real crown will change its size to whoever is wearing it when they say 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.