Yukio Okumura

The deuteragonist of this work. Rin's twin brother (fraternal twins). A middle first-class exorcist. Titles obtained are Dragon Knight and Medical Engineer Knight. 15 years old. Born on December 27, just like Rin. Blood type O. Height 180 cm, weight 70 kg. Ambidextrous. Belongs to the Special Advancement Class 1-A at True Cross Academy High School.

He wears glasses. Normally serious and gentle-mannered, calm and composed, which is the opposite of Rin's personality, but when he gets angry, his calm demeanor collapses and a rough tone emerges. An honor student excelling in both academics and athletics, he entered the special advancement course at True Cross Academy as the top student, making him popular among female students. On the other hand, his cooking skills are not as high as his brother's. His dream for the future is to become a doctor. He is complexed about having many moles on his body, to the extent that he has nightmares about getting more moles. Despite his appearance, he is competitive and tends to keep his worries to himself without consulting others, including the matter of being recruited by the Illuminati from Todo and Lucifer, which he has not discussed with anyone, and has been advised by Shura and Shima about it. Because of his serious and suppressive attitude, Shura points out that he is the type "likely to fall into demonhood," and he is being tempted by Todo, who has fallen into demonhood.

He was exposed to Rin's blue flames in his left eye at birth, causing him to suffer demonic interference, and he could see demons by the time he was aware. Unlike Rin, who grew up without knowing anything, he was informed at a young age that he and Rin were the offspring of Satan, and was encouraged by Shirou to become an exorcist. He became an exorcist to protect Rin from demons, and after the death of his foster father, he became even more determined. He started learning exorcism at the age of 7 and became the youngest exorcist in history at the age of 13. In combat, he mainly fights using dual pistols. According to Mephisto, he is a "genius in anti-demon pharmacology" and has been teaching anti-demon pharmacology at the exorcism cram school since his first year of high school. He can perform impromptu demon summoning using magic bullets, but he himself says he has no talent as a Knight. Shura, his senior disciple, teases him a lot, which he finds difficult to deal with. According to Lightning, he has the skills of an advanced level, just not having taken the promotion exam.

He was born weak and premature, so he apparently did not inherit Satan's powers, and although he has undergone tests, there are no abnormalities at the moment. However, during a battle with Todo, his eyes change, and his vision turns blue, a phenomenon that occurs, and thereafter, something inside him protects him when death looms. In the Izumo arc, Lucifer recognizes his latent abilities and he receives an invitation to join the Illuminati. During this time, being told "You are weak" starts to make him anxious, and he dismisses Rin's concerns and secretly conducts dangerous experiments to explore the true nature of his abilities, but after being injured in the fight against Hachirota, he begins to reflect on his narrow-mindedness. However, after Shura talks to him about his mother, he deepens his worries about his own existence, becomes tired of hurting people around him selfishly, and attempts suicide by gun, but fails due to Satan's interference. On January 2 of the following year, he is detained on suspicion of shooting Mephisto, but escapes and joins the Illuminati with Renzo.

After undergoing a thorough examination in the Illuminati, it is confirmed that he is an ordinary human with no resistance to any demonic possession, but at the same time, it is discovered that he has an abnormally high resistance to the blue flames due to being in the same womb as Rin, and similarly, the red flames of the material world and the black flames of the void also have no effect on him. Then, after receiving the Alm Mahel gun, which only he can use, and healing his broken left arm, he betrays the Illuminati, summons Futen and Raiten using "Morinas's Covenant," and goes on a rampage as "The Master of Boundaries." Later, he reunites with Rin, but due to differences in their wills, they engage in combat, overwhelming Rin while venting his pent-up feelings, but after hearing Rin's true feelings, he becomes aware of his feelings for his brother and reconciles.

Techniques used:

Naias (Water Spirit)

Naiades Carcel (Water Spirit's Water Prison)