The story centers on Rin Okumura, a fifteen-year-old teenager who, along with his twin brother, Yukio, was raised in a church by Father Shiro Fujimoto, an exorcist. One day, Rin discovers that he and Yukio are children of Satan and that Yukio intends to take him to Hell with him. After witnessing Shiro's death, Rin unsheathes Kurikara, a sword that contains his demonic powers stored within it.
