Rapp was a young Cêpan who was training in Defense Engineering at the Lorien Defense Academy. He was one of the two trainees along with Sandor whom he shared a room with. Rapp is described as having small nervous eyes, a wide mouth and a bulbous nose. Along with Sandor, Rapp was chosen to be part of the Defense Engineering Training program because of his intelligence. Opposite to Sandor, he felt that the safety of the planet was incredibly important, to prevent the Elder's Prophecy, and felt blessed that he was playing a small but significant part in it. He often defends the system against Sandor's attitudes towards it.