Yukio Okumura is one of the main protagonists in Ao no Exorcist. He is also Rin's younger twin brother. A straight arrow and kind-hearted by nature, his goal is to become a doctor. Unbeknownst to his brother, he is a brilliant exorcist - the youngest in history -in short, a genius. His abilities are gradually unveiled during his time at the Exorcism Cram School.