Riley is the daughter of Onyx, a gem who fought on the side of the home world gems in the Great Gem War. She was used as a way to kill rebels and lure her uncle Ajoite into giving himself up. He sensed danger and saved Riley from a possible future in villainy. She has no memory of her life from that point back. she only remembers being with Ajoite and the others. Her training for the return of the home world was rigorous, but she thought it was just gem tradition.