Sion is well loved by his people and his servants, and considers Ryner to be his best friend. However, within his own court, he has to deal with numerous antagonistic plots from the dissented nobles who preferred the old form of tyrannical rule, and when one of these plots killed Fiole, a commoner he befriended who became his personal assistant, he is filled with pain at his lack of power to prevent that. Sion is a tactical genius and perfectly willing to make sacrifices so the greater good can be accomplished, even if the method is often extreme, though he is frequently troubled when forced to choose between the lesser of two evils. During his reign as king, he is often torn by the knowledge that sacrifices had to be made as a result of his decisions to achieve his goals, which includes the conducting of inhumane experiments on other bearers of the "Cursed Eyes" to harness their powers as weapons, the killing of less to save more, and that sooner or later he must kill Ryner to secure his kingdom from within. He once remarked that while he wished for the same end as Ryner, the means by which he intends to use to secure the end greatly differs from that of Ryner's ideal. When Ryner received a note citing if he loses control of his power he will be put to death from one of Sion's soldiers, Ryner decides to join up with Tiir which cause the two to part ways. Sion become greatly distressed despite putting up a strong front toward his people until Lucille triggered the awakening of "The Mad Hero" in Sion's body.
Following the awakening of "The Mad Hero" inside Sion, he tries to kill Ryner to prevent "The Mad Hero" from devouring Ryner sending him to hell but fails to do so. Sion then gives his body to "The Mad Hero" who starts conquering other countries.
Because of a contract made with "The Mad Hero", the first King of Roland, enemy of "The Goddesses", "The Mad Hero" now resides in Sion and slowly consumes him from within, gradually leading him to suddenly exhibit moments of a split personality from time to time. In order to reach the territory of "The Goddesses", Sion initiated the invasion of Roland's former allies, which includes Imperial Nelpha and Runa Empire, and conquered the southern part of Menoris. Thereafter, he was betrayed by ally Remurus Empire and lost a part of his land as well as Calne, who appeared to be captured in the battle.
Voiced by: Daisuke Ono