The fictional characters from the manga and anime series Blue Exorcist were created by Kazue Kato. The story revolves around Rin Okumura, a teenager who discovers he is the son of the god demon Satan, born from a human woman and the inheritor of Satan's powers. When Rin's guardian dies while fighting Satan, Rin decides to become an exorcist in order to defeat his father. Entering into the True Cross Academy to learn how to fight demons, Rin meets several other exorcist apprentices whom he starts to bond with. Critical reception to the characters has been positive for their traits and interactions.
Main characters
Rin Okumura
is the fifteen-year-old protagonist of the story. He is a son of Satan, born from a human woman and is the inheritor of Satan's powers. His powers were sealed at birth into the demon-slaying blade by Mephisto Pheles, the True Cross Academy principal, allowed him to live a normal human life for nearly 15 years with his twin brother Yukio and his foster father Shiro Fujimoto. Rin becomes aware of his true identity after Kurikara can no longer seal his powers, setting off a chain of events that lead to the death of Shiro at the hands of Satan, who attempts to drag Rin back to the demon realm, Gehenna. Mephisto Pheles later confronts Rin, who demands that Mephisto let him join the exorcists to fight against the demons. Mephisto Pheles—the director of True Cross Academy—personally enrolls Rin into the True Cross Academy so that Rin can pursue his goal to obtain the title of "Meister" in Knight, then become a Paladin and defeat Satan. He also wants to earn Yukio's respect. While currently an Esquire, Rin wishes to obtain the highest rank of an Exorcist, Paladin, to prove Fujimoto did not want to use him as a weapon. Rin is also a good cook, preparing meals for himself and Yukio.
Rin can access the power he has inherited from Satan through drawing Kurikara. The sheath acts as a portal to Gehenna, which, when the blade is drawn, returns Rin to his demon form. While in his human form, Rin exhibits a number of physical traits that are signs of his demonic nature that are intensified in the demon forms. In both forms, Rin can control incredibly destructive bright blue flames, the trademark sign of anything related to Satan. However, when he draws Kurikara, the magnitude of the flames dramatically increases and often leads to Rin being "consumed" by his own flames and losing his mind. Rin later meets a spirit named Kongo Ucchusma who teaches him how to control his flames (in the anime, this was changed to Shura and Yukio who helped him). Rin also has a Cat Sith, Kuro, who was initially Shiro's, as his familiar, and it has 2 tails like a nekomata. When Yukio awakened Satan's power in his eyes and shot him, the demon part of Rin awakens and for a moment takes over his body and nearly kill his friends when he unleash the full power of Satan's flame until Rin takes back control. The resulting awakening caused Rin's appearance to change to similar in appearance with his demonic self.
Rin is voiced by Nobuhiko Okamoto in Japanese and by Bryce Papenbrook in English, while in VOMIC he is voiced by Daisuke Namikawa. In the Blue Exorcist musical, he was portrayed by Ryou Kimura.
Yukio Okumura
is Rin's younger fraternal twin brother. When it was discovered that the woman impregnated by Satan was going to have twins, it was believed that Satan's powers would be split between them. Due to the weakness of Yukio's body, however, he did not inherit any of Satan's power, thus being born fully human with the full extent of Satan's powers going to Rin. Yukio did, however, receive a spirit wound at birth from his brother, which allowed him to be aware of demons for as long as he can remember. Yukio secretly trained to become an Exorcist from the age of seven in order to protect Rin through the help of Fujimoto. While both Yukio and Rin are in their first year at True Cross Academy, Yukio is already an instructor at the Exorcist cram school teaching Anti-Demon Pharmacology to Rin's class.