Hilarion is a prince from the Isle of Adamant. When he was just a boy he was betrothed to a princesses. When he was older, he was hit by a forget whirl and forgot her name. He searched twenty years for her looking young until he found her, but also because of the forget whirl, he did not know how long he had been searching. It turns out he was betrothed to Ida when she was just two years old. He would know his betrothed upon kissing her. Since their marriage, Hilarion and Ida have had Ione, who appeared in Esrever Doom where he was mentioned.