"I'm not your weapon; Demon King or savior! I'm Rin Okumura! And when I'm done, I'm going to be the best Exorcist you ever laid your eyes on!"
Rin Okumura (奥村燐 Okumura Rin) is the son of Satan and the elder, fraternal twin brother of Yukio Okumura. Studying as an Exwire at True Cross Academy, Rin desires to earn a Knight Meister and defeat his biological father.
Rin has messy, jet-black hair (dark blue in the anime) that sweeps down in his pale skin and intense blue eyes. Since using Kurikara for the first time, Rin began exhibiting a number of physical traits that hint at his demonic nature in his human form such as prominent canine teeth, slightly pointed ears, and a black; fur-tufted tail just above his hips.
In his Demon form, Rin gains two horn-like blue flames floating above his head, long elf-like ears, and slit-like red pupils while his irises remain a deep blue. The blue flames also blaze around other places of his body, mostly at the tip of his tail.
Before going to the True Cross Academy, Rin's wardrobe consisted of a simple blue hoodie over a pink T-shirt and a pair of black jeans with chains on the side, giving the impression of a rebellious nature. He was also seen wearing a white jacket with big pockets and various decorations on it and a fingerless pair of black gloves. Because of how often he got into fights, Rin was seen with band-aids over his cheeks and fingers, wounds which were usually taken care of by Yukio.
While in True Cross Academy, Rin wears the school's uniform, which consists of a white shirt, a loose necktie, a black jacket, and black pants. He is also seen carrying around Kurikara in a red sleeve over his back and shoulder with a black strap. In class, he is occasionally seen with his bangs pinned up so he can read his studies.
Rin has a protective and supportive personality. Rin can be very violent and get into fights (possibly caused by his demon side), but really has a kind heart. He supports his friends and tries to encourage and help them. He also seems very protective of Yukio, and aims to surpass him one day. However, Yukio often finds Rin annoying due to his frequent impulsiveness and stupidity, which makes Yukio look down on Rin as much as up and makes it hard for Rin to be taken seriously by Yukio and even others, making Rin desperate to earn his brother's approval. He takes offence when Yukio accuses him of killing their father and pointing a gun at him, warning him not to insult him and saying that he isn't going to fight his brother.
Although he generally hides it, Rin loved his adopted father a great deal, and has nothing but good things to say about him. He deeply regrets that the last thing they did was fight, which resulted in Satan taking him over. Much like Yukio, he takes any insult against him very seriously, and got really angry when Shura claimed he died like a coward. He also doesn't like people insulting Yukio, who he loves and greatly respects. Besides this, however, Rin is surprisingly even-tempered and laid-back, and rarely gets angry without a good reason.
Rin is often shown to be able to relate to people easily and connect their feelings to his own, such as Shiemi Moriyama's grief over her grandmother and Ryūji Suguro's ambition to defeat Satan. He's also able to understand Shiemi's desperate desire for friends, as he grew up with almost no friends due to being constantly harassed by bullies and being called a demon. In general, he is often the first one to try and make people feel better if they're down. He's not the type of person for school or studying, though he was able to gain a junior high diploma and become an Exwire.
Unlike his brother, Rin is immature, which leads other people into believing that he is younger than Yukio; it's been noted by several people that despite being twins, he and Yukio couldn't possibly be more different. He is headstrong (literally as well as metaphorically, as he was able to stop a charging demon by directly headbutting it in the forehead) and is often very open with his friends. However, when his friends found out about his demon heritage, they become afraid of him, thinking that he is unstable which could lead to a disaster, but they slowly got used to him and accepted him during the Kyoto Arc.
Despite his usual hot-blooded, headstrong attitude, Rin is often shown to be more sensitive than he lets on, which is shown when he cries from reading an emotional drama manga. He is also shown to have a soft spot for animals. In the beginning of the manga, the reason he had gotten into a fight with Reiji Shiratori and his delinquent gang was because they were torturing pigeons. He also attempts (successfully) to tame Kuro without killing him after hearing that he was once Shiro's familiar.
During the time of the Blue Night, Satan murdered a huge number of the world's greatest holy men, in order to find someone who he could possess without any ill effects to save Yuri Egin, who was going to be executed by the Vatican for being impregnated by him. Shiro Fujimoto and Mephisto Pheles were ordered by Yuri's father, Ernst Frederik Egin, to go find and kill her and Satan's children. They found Yuri within the forest with her newborn twins, whom she named Rin and Yukio , and she soon died of childbirth. Instead of killing the twins, Shiro decided to seal Rin's Demonic powers within the Demon-slaying blade Kurikara with the help of Mephisto, and raise Yuri's children as his own. Mephisto then made a deal with Fujimoto that if he doesn't succeed in raising the twins as normal children and if Rin's Demon powers ever came out, they will be under his custody.
In his childhood, Rin led a normal human life, but his strength and temper seemed unnatural, so all the children and even teachers feared him and thought of him as a Demon, throwing slangs such as 'Demon child.' He got into fights often and injured all his classmates, and the only one who could stop him was Shiro. Rin always admired Shiro and wanted to become like him when he grew up. Rin always protected Yukio from bullies and encouraged him to chase his dream. Also in his youth, Rin learned how to cook, which became his natural talent.
After getting into another fight with Reiji Shiratori and his gang, and being fired from another one of his part-time jobs, Rin's guardian, Shiro, strictly reminded Rin that he would have to make a living on his own someday. After Yukio treated Rin's wounds, Yukio asked him if he would be alright without him around since he was going to move from the church. Rin admitted that he was also worried, but he said that he had done nothing wrong. After being prompted by Izumi and Maruta on going to the job interview, Rin saw Shiro consulting a girl named Yui Sakamoto and commented that being an Exorcist must be hard with having to get rid of things that don't even exist, to which Shiro disagreed and claimed that Demons exist within human hearts.
Later, after Rin called Yukio that he was able to get a job at the supermarket (with the help of his natural talent at cooking), he saw Yui chasing after her scarf. When Rin caught the scarf and was about to give it back to her, he suddenly saw a monkey-like creature there took the scarf out of his hand and ran off. While Rin was chasing after the creature as they thrashed around in the supermarket, it suddenly went on top of some boxes, which were going to fall on Yui. Rin protected her from them, but the girl fell unconscious. Shiro, Yukio, and the others were waiting for Rin to come home to celebrate, but Rin was nowhere to be seen. Worried, Yukio went outside to look for him, and eventually found Rin at the park. Rin told Yukio that he was too ashamed to come home after he got fired from his job, but couldn't explain him why. Then, when they both arrived back home, Rin saw Yui again, along with her father, who came by to thank Rin for saving her.
The next day, after he woke up and saw a letter from Yukio saying that he had to leave earlier than planned, Rin started to see a lot of small black creatures floating in the sky. He went outside and began to wonder why no one around him was noticing them. Then suddenly, Reiji and his gang appeared and asked Rin to come along with him to have a talk. At the alley, Reiji said that he came to apologize and tried to give Rin some money as a request for him not to mention about the fight that they had the other day, as it would damage his own reputation and his chance of getting into the True Cross Academy. Rin declined the offer, but when Reiji said that he should accept the money because his family was poor and that Yukio got into the Academy only for his grades, Rin punched him, saying that he could insult him all he wanted, but not to Yukio. Then, as Reiji was about to burn Rin with a heated steel pole, blue flames started to appear from Rin, surprising himself. Astaroth, the Demon whom was possessing Reiji, said that the blue flames were the proof of Satan's offspring and was about to take Rin to him, but Shiro suddenly arrived and exorcised Astaroth from Reiji. Afterwards, a horde of Demons started to appear and attacked Shiro and Rin, to which Shiro stated that they won't stop at nothing to bring Rin to Satan.
When they finally arrived home, Shiro and the other Exorcists placed many protection barriers surrounding the chapel. Shiro also gave Rin the sword Kurikara, which was used to seal his Demonic powers. Then, Astaroth (possessing Reiji again) and his Demon minions started ambushing the church, but the Exorcists managed to defeat them. After the battle, Rin had a harsh argument with Shiro, believing that he just wanted to get rid of him. Mentally shocked from hearing Rin's accusation and hitting him, Shiro suddenly got possessed by Satan who came to drag Rin to Gehenna. After Satan opened the Gehenna Gate, Shiro, managing to regain control of his body, stabbed himself in the heart and proclaimed that Rin was his son before he died. As he remembered his memories with Shiro, Rin drew out Kurikara, which returned his Demonic powers, and destroyed the Gehenna Gate, leaving Rin and Shiro to remain in Assiah.
After Shiro's funeral, Rin stayed behind at his grave. When he was about to call a phone number of Shiro's friend, a phone near Rin rang. To his surprise, he saw a lot of Exorcists surrounding him with Mephisto Pheles. Mephisto gave Rin three choices: him killing them, them killing Rin, or Rin committing suicide. Rin choose neither of those options and instead decided to become an Exorcist, stating that he didn't want anyone else to die. Hearing this, Mephisto became amused and accepted Rin's idea, letting Rin start at the True Cross Academy.
The next day, Mephisto brought Rin, along with Yukio, to the True Cross Academy. Rin was surprised to see Yukio was the year's freshmen representative, but was glad to see his younger brother fulfilling his dream of becoming a doctor. While Rin was looking around the Academy, he later met with Mephisto, who warned Rin to control his temper, as his blue flames would easily respond to his emotions and expose his identity as the son of Satan. With that said, Mephisto gave Rin a magic key that allowed him to enter the school for Exorcists from any door. There, Rin met with his classmates and, to Rin's surprise, Yukio entered the classroom introducing himself as a teacher. Yukio revealed to his older brother that ever since he received a mashou from Rin when they were born, he were capable of seeing Demons, and Rin was the only one who didn't know the truth. As they argued, a vial of foul-smelling liquid accidentally fell onto the ground, which lured a horde of Hobgoblins. While they were fighting them, Yukio called Rin an idiot and accused him for being responsible for Shiro's death as he pointed his gun at him. Rin said that he was right to call him that, but he exclaimed that he wouldn't dare point a weapon at his own brother as he slew a huge Hobgoblin. After the fight, when Yukio asked Rin of how Shiro's final moments were, Rin answered that he was unbelievably cool. Later, Rin found himself sharing one room with Yukio, even though they were the only residents of the entire dorm. Yukio said that he would need to keep watch over Rin, much to Rin's dismay.
Later, when Rin heard from Yukio that he had received an exorcism request, Rin convinced Yukio to let him come with him, as he would learn more out in the field. While Yukio was inside the Exorcist Shop to buy some supplies, Rin noticed another nearby stairway, which leads to a beautiful garden. There, he saw Shiemi Moriyama, the shopkeeper's daughter. At first, she thought that he was a Demon, since he accidentally broke the gate that had a barrier around it, but soon afterwards, Shiemi apologized to Rin as he was helping her with her flowers. After Shiemi talked to Rin about her wish to find the Garden of Amahara, Shiemi's mother brought Yukio to have him examine Shiemi's legs, which were infected by a Demon living within the garden. Shiemi suddenly collapsed after she disobeyed her mother's order to abandon the garden for the sake of her health. After hearing from Shiemi's mother about Shiemi's past with her late grandmother, Rin went to Shiemi and told her that her grandmother never wanted her to be a prisoner of the garden. As soon as Shiemi realized that what she had been doing was wrong, an angry Dekalp appeared and possessed Shiemi. Rin couldn't directly attack the Dekalp since it was using Shiemi as a shield, but Yukio shot a nutrient capsule bullet, letting Rin kill the Demon when it was separated from Shiemi. After the battle, Shiemi was able to use her legs again and reconcile with her mother. The next morning, Rin saw Shiemi introduced as a new student in his class, since she resolved to learn more about the world around her, and as thanks to Rin and Yukio for helping her.
A few days after Shiemi's enrollment, Yukio handed out their test results. Rin had 2/100 correct while one of his classmates, Ryuji Suguro, had 98/100. Ryuji criticized Rin and they got into a verbal fight, but were interrupted when Renzo Shima, Konekomaru Miwa, and Yukio held them back. During the class' P.E. session in the arena, Rin and Ryuji competed in a race to see who would be the last one standing while being chased by a rampaging Reaper. Rin proved to be faster than Ryuji, and in his anger, Ryuji kicked Rin and got into another fight, but their teacher Kaoru Tsubaki stopped their quarrel. After Renzo and Konekomaru explained Rin about Ryuji's dark past and his goal to defeat Satan, Ryuji challenged Rin to touch the Reaper without it attacking him, so he could prove that he was determined to become an Exorcist. Rin declined and told Ryuji that he wasn't stupid to risk his life like that because he also had a goal to achieve. That angered Ryuji, so he went down to toward the Reaper himself to prove he was brave enough. However, the Reaper could feel the anguish from Ryuji's mind and was about to bite him, but Rin quickly jumped in and took the Demon's attack for him. Rin looked at the Reaper in the eye and ordered it to let go. After that, while back in the classroom, Rin tried to study, but he couldn’t concentrate because his bangs were in the way. However, Ryuji then came to Rin and loaned him a hair clip to put his hair up and thanked him for saving him. Rin was surprised and thought it was creepy and an omen, which annoyed Ryuji.
While Rin, along with his classmates, were staying at his dorm for a week to study for the Exwire authorization exams, Rin couldn't help but notice that Izumo Kamiki was treating Shiemi as her servant, which began to worry him. When he confronted Shiemi about it, Shiemi dismissed that notion, exclaiming that she was helping a friend. However, they stopped arguing when they heard Izumo and her friend Noriko Paku's screams coming from the girl's room, and Rin told Shiemi to go bring Yukio as he rushed to their help. After Rin saved Izumo from her two Byakko familiars who were about to attack her for sensing her fear, he fought against the Naberius who snuck into the dorm, while Shiemi came to treat Noriko's wounds. Since Rin couldn't risk unsheathing Kurikara and exposing his true form in front of his peers, the Naberius easily pinned Rin down and started to strangle him. Thankfully, Yukio arrived in time and shot at the Naberius, forcing it to retreat. After that, when Rin noticed a crying Izumo blaming herself for not being able to do anything to help Noriko, he gave her his shirt, telling her to go change.
Next morning, Izumo came to Rin to give back his shirt and threatened him not to tell anyone for seeing her crying, as well as thanking him for saving her. Later, while Rin and his classmates received the Bariyon punishment for having a vicious quarrel in the classroom, Yukio lectured them that no Exorcist should ever fight alone. Shortly after Yukio left for a mission, a blackout occurred at their dorm and the same Naberius appeared again. After Shiemi had her Greenman familiar, Nii-chan, provide a tree barricade to prevent the Naberius from getting closer, Rin volunteered to lure the Demon away from his classmates while they make a run for it. However, the Naberius split itself into two bodies and had one chase after Rin while the other stayed behind to try to bypass Shiemi’s wooden defense. Rin ran to the dorm’s power control room to turn the lights back on, but the Naberius threw him back away from the controls. When Rin exposed his blue flames, one of the Academy’s teachers, Igor Neuhaus, appeared from the shadows. Igor revealed that he was responsible for the attacks on his dorm, so he could confirm that Rin was Satan’s son. Angered by his actions, Rin unsheathed Kurikara and slew the Naberius with his flames, causing Igor to flee from the scene.
When he sees her bleeding, Rin let his blue flames out, incinerating the moths. But the surviving sees they are Satan's flames and fly off to tell their boss. Rin calms himself down and tries to wake up Shiemi when Ryuji appears, asking what the blue light was. Rin's flames were very bright so it was hard for Ryuji to see. Renzo appears, letting out his fear of bugs when the two get a text message from Konekomaru that he found a lantern. They go to the depths of the forest together and find out that it's a Peg Lantern, a type of Demon that wakes up when lit and likes to consume people into its fire, especially women.
Since it was large, the group realized that the mission required cooperation. Konekomaru devises a plan involving the five with Rin pulling the lantern, Shiemi feeding it so its flame won't go out, and the three Aria deflecting themselves from the moths. Rin stops, where the group is in front of a bug swamp with a broken bridge. Ryuji has an idea to have the Peg Lantern cross the swamp. Rin carries Shiemi and Ryuji awakes the Lantern. Seeing Shiemi, it goes after her. When it crosses, Renzo and Konekomaru at the other side seals the Demon. Everything went okay until Rin is attacked by the giant moth. Rin tells them to leave, but Ryuji saves him by sealing the moth. They run off with the Peg Lantern as Ryuji tells Rin he helped as Rin helped Ryuji get over his embarrassment of saying he'll defeat Satan. He, Renzo, Konekomaru, and Shiemi tell Rin that they are his allies and will be there for him. Rin is glad but starts to think what happens if they find out that he's the son of Satan.
The group arrives to find Takara and Izumo had already finished their part of the mission. Then, Amaimon appears and unleashes his pet Hobgoblin, Behemoth. Seeing the students in danger, Shura protects the area with a magic circle and dumps holy water on them (except Rin). Shura suggests that Rin should fight Amaimon and gives him Kurikara. Rin is unsure about the choice when Shiemi suddenly walks out of the circle. There is a bug inside Shiemi controlling her and Amaimon kidnaps her. Rin goes after her and Ryuji, Renzo, and Konekomaru follow with flares. Amaimon tries to provoke Rin into using his sword by making Shiemi his bride or threatening to pluck out her eyes. The three monks-in-training intervene where Konekomaru accidentally puffs up Amaimon's hornlike hair. This provokes Amaimon by hitting Renzo and breaking Konekomaru's arm. He strangles Ryuji who tells Rin why he is acting weird and goes off on his own. Seeing his allies in danger, Rin decides to uses his flames as an act of kindness and fights Amaimon. They go into a heated battle where Yukio find the group injured and head them out of the forest to safety. Meanwhile, Mephisto watches. Rin's flames start to increase as he fights Amaimon. He was about to slice him, but Amaimon stops the blade.
He recognizes that Rin's flames are as powerful as Satan's, their father. Then, Rin lets out a roar of flames that instantly defeat Amaimon. Mephisto claps, seeing that Amaimon has done well and was surprised that Rin is able to defeat him at this level. Then he imprisons Amaimon into a large cuckoo clock only for Rin to slice and destroy it. Mephisto is startled by this. Rin's flames are increasing and consuming him as Rin becomes more violent and beast-like. Mephisto vanishes the clock with Amaimon and subdues Rin by sheathing Kurikara. At this point, the Paladin Arthur A. Angel arrives and confronts Mephisto and Shura about hiding the existence of Rin.
Rin is taken before the Grigori and pinned to the floor by Angel’s sword through his ankle. Mephisto, who is on trial, gives a speech inviting the Grigori to make a bet on Rin’s existence as a weapon against Satan. Rin infuriated by how they are all talking like he is a weapon and not a person burst into flame. He yells, "I am not a weapon! I am Rin Okumura and I will be the best Exorcist you will ever see." The Grigori decide to agree to Mephisto's bet to a degree and decree that Rin must pass the Exorcist exams in 6 months. He will be executed if he fails to do so or loses control of himself. He is put under constant supervision of Shura and Yukio.
After the trial Rin begins to take special lessons taught by Shura. Shura tells him that before any training with swords can be done, Rin must first master his flames. His first test is to light the wicks of two candles simultaneously while not lighting the candle between them. Rin has little luck with the exercise as he is only able to project large amounts of flame, which destroy the candles, as well as Yukio's (who was observing) and Shura's clothing. Yukio is then called to a situation in the city. Shura and Rin leave with him.
Shura, Yukio, and Rin arrive at a taped off section of the city. There is a Demon on the loose that has stolen the left eye of the Impure King from the academy, as well as taken a child hostage. Saburota Todo, an upper second class Exorcist in charge, tells the trio that a miasma (Demon poison) is spreading from the scene, infecting civilians with fatal boils. While they are talking, the mother of the kidnapped child arrives and asks them how her son is. Rin reassures her that the child will be saved no matter what, to which Yukio intervenes and says that there is no definite guarantee that he can be saved. Rin confronts Yukio, asking why he would say such a thing. Yukio snaps at him, saying that Exorcists are not omnipotent and cannot always save everyone, and that Rin shouldn't promise that they can save him. In reply, Rin tells him that Yukio should not decide if he can be saved or not before an attempt is even made.
Yukio, Saburota, and two other Exorcists put on hazardous material suits and enters the miasma-filled area, telling Rin to stay out. Rin disobeys and enters, seemingly unaffected by the miasma. They find the Demon (who is hidden behind a breathing mask and cloak) and the infected child. They confront the Demon only to have it disappear and they find the eye it carried is a fake. Suddenly, Yukio is attacked from behind by Saburota, who reveals that he is possessed by a Demon and has stolen the real eye. Rin tries to take the child outside the area but accidentally burns him when he tries to block one of Saburota's attacks. There is a brief fight after which Saburota disappears taking the eye with him, not before telling Yukio that he reminds Saburota of a younger version of himself- both males were assigned to become Exorcists by their families, unable to live the lives that they wanted to have. He then tells Yukio that everyone has weakness in their hearts, questioning if Yukio would ever succumb to his weakness and become possessed. After Saburota leaves, Yukio then attempts to save the badly poisoned child, but finds himself unable to concentrate because of his words. Stabbing himself with a needle, Yukio is able to concentrate and save the child. Impressed and somewhat humbled by Yukio’s abilities Rin swears to God that he will surpass Yukio, to which Yukio replies with a smile that he shouldn't go around saying that to everyone and that he will not be able to take care of his older brother forever.
Rin is later seen training privately on top of his roof, becoming frustrated at his ability to properly focus and burn only the two candles. Shura comes up, surprising him with her knowledge that she knew he was secretly training every morning. She then throws him a travel guide, informing him that he is going to Kyoto on a mission and that he better prepare himself. While waiting for the train, Rin is reading the travel guide peacefully while Shura, seated in front of him, complains to Yukio that she is in charge of the Reinforcement Squad for the Right Eye. Yukio tells her to take care of Rin, to which Shura replies that he is being too serious again.
Boarding the train, Rin tells Shura how he didn't go to Kyoto for his middle-school trip and that this is his first time, asking her if they should take bananas as snacks. She asks if he is going to keep up this child-like attitude until he has enough fun, to which Rin says that he is excited because it is his first time leaving Academy City. Once they are on the train, Rin asks Shura where he should sit, to which Shura replies that, judging from the looks on the other Exorcist's faces, he should sit away from everyone else. He then says hello to Shiemi, who just walked on, who replies with a frightened hello before walking away. Seeing Ryuji Suguro, Shima, and Konekomaru, Rin says hello and asks them if there is anywhere they'd recommend he visit while in Kyoto. The three walk down the aisle without saying anything to Rin while discussing how they are surprised that Rin is still alive, saying that he could go on a rampage at any second. Depressed, he thinks how it is only natural that everyone would be afraid of him after witnessing his fight with Amaimon. Izumo walks in, turns down Shima's invitation to sit with him, and slides into the seat next to Rin, much to his surprise.
Shura then informs the group about their mission- to reinforce the weakened guard in Kyoto, where the Right Eye of the Impure King resides. Izumo ask the group of Exorcists what the Eyes are. The eyes belong to the Impure King, a Demon who released diseases and epidemics in the Ansei Era (1854-1860), as well as caused the deaths of around 40,000 people. Although the monk Fukaku killed the Demon and removed the eyes, someone is trying to steal them and do evil things with them. Shura finishes by saying that their specific duty is to nurse the injured Exorcists who were attacked by someone trying to steal the Right Eye, as well as reinforcing their guard.
When Shura finishes, Rin turns to Izumo and asks her if she is afraid of him. She says that she isn't because many people and Exorcists around the world are related to Demons by blood. Shocked, Rin listens as Izumo says that the reason why so many are afraid of him is that he is the son of Satan, and that no one knows if he will become a boon or bane to the Order. Nevertheless, no one should be making such a big deal out of his heritage. Rin, touched by her words, calls her "Eyebrows" affectionately, and says that he always knew she was a good girl. In reply, Izumo yells at him, asking how he came to that conclusion and why he calls her "Eyebrows." Rin just thanks her, while Izumo replies that it isn't anything, she just hates cowards who run away from friends at crucial times, like Ryuji and Shiemi. Angered, Ryuji calls her a bitch, causing all of the Exwires to be punished.
While the group are being punished, Konekomaru asks why Rin is being let out on a mission, saying that he is dangerous. Suddenly, the rock Demon on him flies off and lands on Shiemi, pinning her to the floor. The group tries to remove it but are unable to because the particular rock Demon used to punish them can only be destroyed by high amounts of heat. Rin tells everyone to move aside and walks up to the rock and tries to lift it, but he is unable to. He then sets his body on fire, scaring everyone except himself and Shiemi, who says that the flames are not hot but warm. Ryuji tries to grab Rin to push him away from her, but ends up grabbing the flames and throws it into the cabin, spreading the fire around. Izumo summons her familiars to create holy wine to put out the fire. Meanwhile, Rin grabs Ryuji and asks him why he got in the way, saying that he had everything under control and that he should have faith in his abilities. Ryuji, extremely angered, asks how could he not try and force Rin away from Shiemi, saying that those blue flames can kill people. He goes on to explain that, during the Blue Night, his grandfather, Shima's grandfather and eldest brother, and Konekomaru's father died because of those flames, and asks Rin how could he ever trust those flames. Rin says that the death of so many people close to them must have been horrible, but it has nothing to do with Rin. Konekomaru intervenes, saying that, as Ryuji intends to defeat Satan, he shouldn't do risky things on his own.
Shima then yells at Ryuji Suguro to watch out as a rock Demon flies at his head, which is intercepted and sliced by Shura. She then yells at the group, saying how if they cannot take on small Demons and can only hamper one another, how would they be able to fight real ones. As they exit the train station, Rin stares at the Kyoto Needle with a sad expression on his face. The group then arrives at the inn they are staying at, which turns out to be the inn Ryuji Suguro, Shima, and Konekomaru grew up in. After being introduced to the head of the inn, Ryuji Suguro's mother, the group heads over with Yunokawa to help nurse those infected with miasma while the three Kyoto members go see their families. However, Yunokawa instead tells Rin to "collect something," like trash or something. Rin notes that there isn't much around to collect, mostly hair. Kuro, who is with him, finds more hair, which turns out to be Adachi's, which Rin tries to pull from his head. This makes Adachi angry, and Rin asks him to give him something to do. Adachi tells him to ask Kinoshita, who tells him to ask Yamagami, who tells him to ask Kawanaka, who finally sends Rin back to Kinoshita, causing Rin to realize in anger that they want him to do nothing.He goes to help out one of the head priests, who reveals himself to be the head priest of Fukaku's temple, Ryuji's father Tatsuma Suguro. The two discuss Ryuji, and, after Rin sees Shiemi, Tatsuma slips away. Later, Rin walks into an argument between members of the Shima family and the Hojo family, stating that he thought Kyoto would be more elegant than he has seen it.
Rin continues to struggle during his training to control his flames but eventually was able to manipulate his flames at will once. Tensions rise when a traitor amongst the monks is discovered and Suguro demands answers from his father. Suguro argues with his dad which makes Rin remember how he told Shiro not to act "fatherly" before his death. Rin berates Suguro to apologize to his father. When Suguro refuses, Rin loses control of his flames exposing his parentage to the monks. Shura is forced to render him unconscious with an imprisonment spell. Rin is put in a prison where Shura gives him a letter from Suguro's father. The letter informs them and Yukio of how the sword Kurikara originally belonged to the monastery and that Shiro took it to kill kids (supposedly Rin and Yukio after they were born). He requests that Rin defeat the Impure King whose body is hidden in the temple as Rin's flames are capable of defeating him.
However when Rin tries to unsheathe the sword, he cannot. Shura realizes that Rin has lost his confidence because of his earlier loss of control. Mephisto arrives and announces that Rin has been sentenced to death. He then summons "the strongest prison" and puts Rin within it. Meanwhile, Saburota has revived the Impure King and Shura fearing they will be unable to defeat him sends the Exwires to free Rin. Inside the prison, Rin wonders if he should have been dead and why Shiro let him live.
Shiemi manages to get into the prison to save Rin. Fearing for her safety, Rin tells her to leave him alone believing he will hurt her. Shiemi refuses when Rin tries to scare her off by igniting his blue flames. Shiemi, realizing how foolish she was, hugs Rin, restoring their friendship. Shiemi gives Rin encouragement to break out of the prison and he is surprised to find all his friends by his side. At this point Rin reconciles with Konekomaru and the others. Suguro tells Rin he will lead him to fight the Impure King as all the monks and Exorcists gather for the battle.
Rin and his friends proceed to the battlefield and are horrified at the scope of the Impure King. They contact Shura and are asked to find High Priest Tatsuma, Suguro's father, who has gone missing. They find him collapsed in the forest badly injured. On approaching him the Demon Karura appears and declares that it is fulfilling a personal contract to Tatsuma. Tatsuma regains consciousness and tells Rin how to defeat the Impure King. The Impure King will continue to grow and will eventually grow a sporangium that will release a toxic miasma. The weak spot of the Impure King, its core, lies within the sporangium. This core is the combined eyes of the Impure King. Tatsuma explains how he attempted to use a technique called Gouhaen with Karura, which converted his life into flames to stop the Impure King but was unsuccessful. He then tells the group that he will use his remaining life to hold back the miasma should it be released. During this time Rin should destroy the core. Ryuji Suguro objects and Karura's contract is switched to Ryuji Suguro by relation of blood, so that Tatsuma may live. Tatsuma teaches Ryuji Suguro what he must know and collapses. Shima and Konekomaru leave to go tell Shura and the Exorcists what has happened. Izumo and Shiemi stay behind with Tatsuma. Suguro says he will but up the barrier but he must get close to the sporangium. Rin declares that he will protect Suguro and the two head towards the Impure King.
Rin and Ryuji Suguro get close to the Impure King and see that it is starting to take on the shape of a building. Ryuji Suguro urges them to hurry and Kuro comes out of the Forest. He warns Rin that it is dangerous and tells him to run away. Rin refuses so Kuro transforms to his bigger form and tells Rin he will come with him. Rin and Ryuji Suguro climb onto Kuro to get a ride. Kuro gets them as close to the Impure King as possible and they land on a rock so that Ryuji Suguro can put up a fiery shield that manages to contain the Impure King and keep the poison contained for the time being. Rin and Kuro fight to protect Ryuji Suguro from the Impure King while he is in physical contact with the earth but Rin still can't manage to draw his blade. As the fight continues things start to look really bad as the sporangium finally erupts and the Impure King finally shows his true form.
The Impure King then targets Ryuji Suguro but Karura manages to protect Ryuji Suguro by shielding him in a cyclone of hot wind and flames. It works and drives the Impure King away from Ryuji Suguro but this line of defense weakens Ryuji Suguro twice as fast and the shield will only last for 15 more minutes before Ryuji Suguro runs out of strength and it disappears and thus unleashes the Impure King completely. Rin tries to draw his sword but even with the situation getting worse by the second he still cannot draw his blade. Ryuji Suguro tells Rin to run while he still can and get to safety. Rin then says that he wants to visit the Kyoto Tower and that Ryuji Suguro can show him tomorrow, that's why Rin wants everyone to be safe, so that they can go visit it. Ryuji Suguro then asks why he would want to go there in the first place (he himself has never been there as he finds it embarrassing) when Kyoto has much better tourist attractions, to which Rin replies that he's wanted to visit the tower ever since he saw it and because he doesn't know that much about temples and would prefer to see some of the fashion spots. Ryuji Suguro then laughs and says that he'll support Rin's fake confidence because they're friends and because he trusts Rin.Rin, after hearing this, asks himself why Shiro saved him, why was he saved. Finally, Rin was able to draw the Kurikara and begins to fight the Impure King with his flames proving to be very effective. Shura shows up and says that she'll protect Ryuji Suguro while Rin faces off to fight the Impure King, telling him to prove to her that Shiro was right in letting him live. Ryuji Suguro soon runs out of energy to maintain the protection, and the fire shield that had contained the Impure King vanishes, and the sickness-inducing miasma begins to spread down the mountain towards the city. Rin is desperately trying with all his might to cut and burn down the Impure King before it reaches the city when, from out of his sword, comes the sworn enemy of the Impure King, Ucchusma.
With this new power, Ucchusma then tells Rin how to control his flames and how to use them to defeat the Impure King by summoning Kashou Zanmai which will burn everything in the material world and allow for Rin to purify everything on the mountain. Rin is hesitant, and protests against using such power because he does not wish to harm all the people fighting on the mountain as well. Ucchusma shows no concern for any of their fates, and displays only an uncaring apathy towards the other Exorcists' well-being when he retorts that there is no time to be thinking about such trivial things and that everything and everyone contaminated by the Impure King must be purified now. Before Rin has much time to think on this, the Impure King nearly hits him with one of its attacks; he is still not sure whether he can defeat the enemy without hurting anyone, but decides to try and then starts the chant as the words come straight to him in his head. He finishes the chant with Ucchusma's encouragement, and releases a massive fireball at the Impure King's body mass only to find it is still not enough. The fire Demon demands to know why Rin is not putting more power into his flames; but Rin mentally states to himself that if he puts any more power into the flames, he'll be burned out, and the flames would consume him.
Still, with one more effort, he shoves more power into the flames. Rin then begins to slowly slip out of control as his own flames begin to overwhelm him, and rip his self-restraint apart. With his control almost gone out of his reach, the son of Satan snarls to himself that his power has been repressed since his birth and that he has had to put up with that! He cries out for it to stop while thinking to himself that he has had enough; his power and himself is now free, and he will rip everything to pieces, a beast that burns everything to ash.
But, placed on the every edge of losing his grip on his humanity, Rin suddenly remembers what Shiemi had said to him when she appeared in the jail; "I'm not afraid." She was completely unharmed by his flames and it was because Rin himself made it so. He recalls all of his friends and how they all put their faith in him, how they trusted him, and he decides he wants to live up to their faith and expectations. Confident once more and no longer struggling for control, Rin, armed with this new revelation, calmly unleashes as much power as he can on the Impure King's monstrous form. He succeeds in completely scorching the Impure King from Assiah with a blinding explosion of light, and sending waves of brilliant, bright blue flames down the mountain, burning everything that had been contaminated and destroying all of the bacteria. The flames do not burn away anything BUT the Impure King, and everything on the mountain is purified of the sickness. However, nobody on the Exorcists' side is harmed or burned by the flames as all; Shima even describes the flames as being warm to the touch, yet not painful at all.
Rin staying alone by himself on the mountainside in the dawn's light, looks onto the mountain, now completely cleansed of the Impure King's taint, and with the repulsive, massive monstrous creature itself defeated. Ucchusma appears before Rin once again, flatly stating everything has been purified, and he's leaving now. He then wonders aloud whether Rin is a human, or a Demon and disappears from Assiah with one final parting remark to the son of Satan on regards to which one he is; "One day, you will have to decide."
Terror of the Kraken arc
True Cross Academy Festival arc
Rin meets a boy in his regular classes at True Cross Academy named Godaīn who recently developed an ability to see Demons. Rin decided to explain the existence of Demons to him but become curious when Godaīn claims to have never received a temptaint. He asks other Exorcist on Godaīn's behalf if there is way for him to stop seeing Demons. Meanwhile Arthur A. Angel easily defeats the powerful Impure Princess, who has powers similar to the Impure King. He voices irritation over the fact that he (Arthur) was not called to upon to defeat the Impure King, and Rin was the person who defeated the Demon. Afterwards he and several other Exorcist discover an artificial Gehenna Gate, and ask Mephisto if he can close it. Mephisto states he can slow its opening but cannot close the gate permanently.
Mephisto Pheles invites Rin to his mansion to celebrate Rin's execution being postponed. He then transports Rin to Gehenna and reveals that he is actually the King of Time, and one the princes of Gehenna. Afterwards he summons the Cukoo Clock Amaimon was last seen in and allows Amainmon to briefly battle Rin. Amaimon releases his full power and seemingly wins rather easily before Mephisto ends the fight and transports Rin back to Assiah. Mephisto hints that Rin is not yet powerful enough to defeat Amaimon. Mephisto then shows Rin special eyewash that could help Godaīn but asks Rin to do an assignment for him. Mephisto once again congratulates Rin on his suspended execution and says Rin must master the Demon's etiquette.
Later that night, Rin and his friends are tasked by Yukio to solve the True Cross Academy's Seven Mysteries (Mephisto's assignment for Rin). The first is a ghost in a wedding gown which does not bother women; thus, the guys try to get rid of it. They learn that the ghost is actually a male transvestite. Rin can't do anything because ghosts can't be hurt by physical attacks, and Suguro and Miwa's Aria is also ineffective against it. The ghost starts trying to kiss the boys and their formation falls apart; after seeing this, Nemu Takara turns his puppet into a male fashion doll and the ghost disappears with no regrets. Yukio then goes over the next mystery which is an evil ghost in girl's bathroom and only appears in front of women.
The next morning, Rin and Yukio have breakfast together. Rin asks Yukio if he is hiding anything to which Yukio says it's nothing. Shiemi stops by shortly after asking where Yukio is, and they wish each other luck on the mission. Rin and the other guys watch Shiemi and Izumo defeat the evil ghost. The girls laugh really hard seeing all the men dressed as girls.
The next day, the Exwires take on two of the mysteries. The first is a statue of Mephisto that moves at night which is exorcised by Rin destroying it with his sword. The second mystery is an unmanned tram that is also solved by Rin destroying it. This angers Suguro the next morning, as he hates how Rin does everything by himself. Miwa then spots Godaīn who had been absent from school for a while, and Rin talks to him, then casually reveals he is half-Demon. After school, Rin and company go to the room of portraits as their next mystery. Mephisto substitutes for Yukio, who was sent to the Vatican, and reveals that this is the last mystery they had to solve as the other two were already solved by him. After they look at the portrait for a bit, Rin decides to slash it and starts to hallucinate. Miwa breaks the illusion and reveals that a shape-shifter has possessed the portrait. Miwa then starts pointing out everyone's faults and tells Rin that if he does everything, the rest of them will not be able to fight without Rin. Miwa devises a plan that uses everyone's abilities and as a team, they destroy the shape-shifter. Mephisto then gives Rin the eyewash and Rin quickly delivers it to Godaīn. He then asks if Rin is scared being half-Demon; Rin replies that he is but has great friends that help him deal with it.
Rin sleeps in on Sunday morning and is surprised to hear Yukio will be meeting up with Shiemi. When he asks him if it's a date, Yukio answers ambiguously. Later, Rin sees Godaīn in class and learns that he hasn't used the eye drops yet. Later, Rin goes to Miwa and Shima's dorm and sees Miwa using a computer to analyze data about different Demons. Shima then mentions the school festival to which neither Rin or Miwa know anything about. Godaīn tells Rin about the food and the dance party; the latter freaks Rin out because a lot of great bands would be there but a female partner was required. Out of the Exwires, Izumo was the only girl they could ask because Shiemi wasn't a student at the academy; however, Izumo was more concerned with the Exorcist exam in the next 3 months than the dance party. Suguro felt the same about the exam, and Miwa wasn't interested in the dance. Shima then talks about how their first year dance is more important than passing an annual Exorcist exam and tells Rin he will introduce his female friends. However, they have absolutely no luck with getting dates, even when they remember about Paku. They happen upon Suguro who turned down a girl and get angry at him. Suddenly, Shiemi appears and tells them she is now a student at the school thanks to tutoring from Yukio. Rin gets excited, believing he can invite Shiemi to the dance.
He finds Shiemi in the cafeteria and asks her if they could talk. After he asks her if she knows about the dance, she tells Rin she was thinking of inviting Yukio. She explains that she noticed that Yukio has been really busy lately, and she thinks the dance could give him a chance to relax. Rin agrees with her and leaves. He is next seen in Miwa and Shima's room depressed about his Shiemi's rejection, while they try to cheer him up, failing to do so.
In the next day, Shiemi tells Rin that Yukio declined, surprising him. He then runs away after she asks if he is thinking anything bad, leaving her confused.
Exorcist Exam arc
Rin and Shiemi are seen participating in a mission together to wipe out a number of Coal Tars investing an old house. Afterwards, Rin accidently let it slip that he has feelings for her, and Shiemi replies she isn't romanticlly interested in anybody. Rin and Yukio are sent to find the whereabouts of Shura Kirigakure.
Mephisto Pheles orders Rin Okumura and Yukio Okumura to go to Towada Shrine in Aomori prefecture to track down and bring back Shura. Yukio tells Mephisto he would rather go alone, which angers Rin. Mephisto then firmly tells him not to argue and that it is an order.
Meister & Abilities
Flames of Satan (魔神の炎, サタンのほのお, Satan no Honō): Also known simply as "Blue Flames" (青い炎 Aoi Honō), Rin, as the son of Satan, has inherited his father's trademark flames, which as suggested are uniquely blue in color. The majority of Rin's powers are sealed in the demon-slaying blade Kurikara, however he is able to use a significantly smaller amount of flames even when his sword is sheathed, typically when enraged. He later undergoes training to control his flames to prevent them from leaking out, as well as to ensure that he is not consumed and reverted to a permanent feral state when he draws his sword. Rin later gains a small amount of control over his flames however he is still prone to his flames leaking out during bursts of rage. By the time of Izumo's rescue operation, Rin has enough control over his flames to create techniques by channeling the flames that are released through his sword in a coordinated manner.
- Pyrokinesis: The most basic ability that Rin possesses due to his heritage, Rin has the ability to create and control fire with his mind.
- Demon Form: When Rin draws his sword, which acts both as his "heart" and the source of his demonic power, he gains access to his true power. Likewise, this also puts Rin at a severe disadvantage, as he does not keep his tail concealed, which is one of his weaknesses, and it exposes his heart, meaning that if Kurikara is destroyed while it is drawn, Rin will die.
Knight (騎士, ナイト, Naito): Rin is an aspiring Knight Meister, and as such employs a demonic sword as his main weapon, which in his case is the Kōmaken Kurikara. Rin eventually gains enough skill and control with his flames and sword to be able to perform various techniques with his Flames of Satan.
- Flame-Emitting Meditation (火生三昧 Kashō Zanmai): With Ucchusma possessing his Kōmaken, Rin unleashes a torrent of fire capable of engulfing an entire mountain. However, because of his conviction, the flames only burn away the Impure King.
- Satan Slash (サタンスラッシュ Satan Surasshu): Rin channels his Flames of Satan through the Kurikara and fires them at his opponent in a the form of a wave in a manner reminiscent of Arthur A. Angel's Angel Slash.
- Satan Bomb (サタンボム Satan Bomu): Rin stabs Kurikara into the ground and then creates a series of explosions at various nearby points of his choosing.
High-Speed Regeneration: Rin, also due to his heritage, has inherited the demonic power of high-speed regeneration, which in short allows him to recover from fatal or near-fatal wounds at astonishingly high speeds, giving him an extreme amount of durability. For instance, he has shown himself able to close a serious stab wound within mere minutes, and reattach his severed right foot.
Telepathy: Rin has shown the ability to exercise telepathy, but only in instances where the one he is talking to is a higher class demon who is not capable of speaking human language, as is the case with Kuro and Ukobach.
Spectral Awareness: Though this ability was suppressed due to Kurikara's sealing, once Rin's powers were completely unleashed, he gained the natural ability to see demons because of his half-breed status.
Cooking Specialist: According to Shiro, cooking is Rin's specialty, and even searched around for a restaurant job he could have to perfectly execute his talent. Rin later exercised his talent when the Exwires and their supervisors were at the training camp, during which he cooked dinner for everyone, which they all extremely enjoyed.
Enhanced Strength: Per his demonic heritage, Rin has incredible strength, giving him the strength to, even as a child, break someone's ribs with a mere punch.
- His name means phosphorus in kanji which comes from Greek meaning "light bearer." In Latin it means Lucifer, a fallen angel cast down from the heavens.
- Rin's favorite pastimes are: cooking, sleeping, eating, and spacing out.
- Rin's favorite manga genres are: action, comedy, and emotional drama.
- Rin's favorite type of girls are ones that are extremely attractive.
- He is surprisingly good with his hands.
- His cooking repertoire includes a wide variety of Japanese and Western foods.
- Rin's favorite food is Sukiyaki.
- Rin sleeps 11 hours a day.
- He has a "Cool Dudes According to Me" ranking in order from coolest to least cool: Shiro, Ryuji, Konekomaru, himself [Rin], Kuro, and Yukio. Shima doesn't even make the list.
- Kazue Katō states that the twin brothers' names were originally switched around, meaning that Rin's name was meant to be Yukio.
- The original concept of Rin had a personality that resembled Ryuji, being able to crush an apple with his fist. He also had a tattoo-like burnt scar on his face, but Katō's editor didn't want her to do that.
- (To Mephisto Pheles) "Let me join you! I don't care what you people say. I'm not Satan's son. I'm of no relation to that filthy beast!! My only father is the old man!"
- (To Mephisto Pheles) "I'm not a human or a Demon anymore. I have no choice but to go forward! I'll become an Exorcist!"
- (To Igor Neuhaus) "You worried? If this isn't enough for you, don't be, 'cause I'll fight as many times as it takes! As many times as you want! I'm begging ya...don't get innocent bystanders involved!"
- (To the various members of his trial) "I'm not your weapon; Demon King or savior! I'm Rin Okumura! And when I'm done, I'm going to be the best Exorcist you ever laid your eyes on!"