Born in Athlante Castle to then Crown Prince Pol and Crown Princess Riena, Rillon was the older of two twins by several minutes. There was reportedly a prophecy about the birth of the twins that spoke of both gaining royal power, but that the younger would, in the end, hold more. This more or less happened - while Rillon became Prince of Ossetia, his younger brother became the King of Canzalis, a neighbouring country Ossetia had invaded. During their formative years the twins were very close as brothers, and even though Rillon's study time increased as he grew older as he was trained to rule the country, they were never far from each other for very long, even into their late teens.