The Emperor of Rome served as the chief of state of the Roman Empire. According to Kureha Suminoya , Princess Iliya was supposed to marry the emperor as his third wife in order to improve relations between Rome and Helvetia two years before Kanata Sorami joined the Helvetian Army. However, Princess Iliya' s tragic death halted any possibility of ending the war. Eventually, Rio agreed to help end the war by offering her hand in marriage to the emperor. Their marriage helped end the war with the signing of the peace treaty.
In Episode 13, he sent his new wife a world map drawn by Roman scholars. In addition, it appears he supports Rio's dreams and is concerned for his people and decreasing availability of resources.
It is revealed in Episode 12 by Rio that he was a down to earth man, implying he was a kind and understanding person