Akio Ootori

Anthy's older brother, the acting chairman of the academy. Although barely present in the first season of the show, he later plays a pivotal role in the second and third seasons. His given name derives from the Japanese name for Venus, the Morning Star, which is identified with Lucifer. In his youth, Akio and Dios (Spanish word for "God") were apparently one and the same, but he became corrupted and lost his purpose as a "prince". Given the origin of his name and his role in the story, Akio may be compared to a fallen angel.

In the manga, Anthy split the two intentionally; in the anime his fall is more vague — it appears to be catalyzed by Anthy, but likewise also by his own loss of faith in the world which tortures both him and his sister. In order to regain the power he lost when he lost his nobility, he creates the Dueling Game in order to create a Duelist with a sword noble and powerful enough to break the Rose Gate sealing his lost power. In the movie, "Dios" is merely an illusion created by Anthy to hide her brother's flaws so she can have a hero to believe in. In the anime, Akio uses Utena's familiarity with his "better half" to his advantage and becomes her lover.

He expresses a desire to see her as his princess and to relieve her of the burden of becoming a prince. In the end, however, he uses her in the same way he uses all the other duelists, though she rebels against his idea of turning her into a submissive princess. Akio appears to dominate his sister Anthy both personally and sexually; their incestuous and power-driven relationship is key to Anthy's behavior in both the anime (where Anthy is, or pretends to be, held in thrall to her brother) and the movie (where events cause the balance of power to shift dramatically). However, the power is not completely held by Akio, as he is dependent upon Anthy for various reasons.