Renn is one of the major characters in the novel Crystal Mask written by Katherine Roberts. Renn is a novice singer from The Echorium, who is the son of Rialle an believed to be Frenn; an orderly. Renn plays a large part in the second novel (Crystal Mask), he is one of the main characters in the plotline. He is noted for being able to speak half-creature and consequently The Pentangle have a particular interest in him and becomes useful throughout the book.