Rin Okumura

Rin has an extremely compassionate and supportive personality, and a kind heart. He supports his friends and tries to encourage and help them in any way possible. He is also very protective of Yukio and aims to surpass him one day. However, Yukio often finds Rin annoying due to his frequent impulsiveness, stupidity, and his care-free attitude, which makes Yukio look down on Rin as much as he looks up to him, making it hard for Rin to be taken seriously by Yukio and his fellow exorcists, making Rin desperate to earn his brother's approval. He takes offense 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. Rin is also revealed to be emotionally fragile when Yukio begins to show signs of insanity and Rin can't find any way to help him. This is further emphasized when he learns the circumstances behind his birth and secretly believes that he should never have been born. 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, whom he loves and greatly respects. Besides this, however, Rin is surprisingly even-tempered and laid-back and rarely gets angry without a good reason. Unlike his brother, Rin is immature, which leads other people into believing that he is younger than Yukio. Rin can also be very violent and tends to get into fights (possibly caused by his demon side). 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 twice his height by headbutting it)

Despite his usual hot-blooded and obstinate attitude, Rin is often shown to be more sensitive than he lets on, which is shown when he is stuck in Mephisto's mechanical prison in the Kyoto arc when Shiemi tries to rescue him and he denies her, openly crying, afraid of himself. He is also shown to have a soft spot for animals. At the beginning of the manga, the reason he had gotten into a fight with Reiji Shiratori and his delinquent gang was that they were torturing pigeons. He also attempts (successfully) to tame Kuro without killing him after hearing that he was once Shiro's familiar. However, it is shown frequently that there is a darker, more malevolent side to Rin. Once Kurikara breaks, Rin's demonic heart is returned to him, and there is another consciousness within Rin's soul. This one is shown to be notably megalomaniac, obsessed with its own power and destroying everything. In a way, it is a conscious manifestation of Rin's demonic power.

Rin has messy, jet-black hair (dark blue in the anime) that sweeps down on 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 long, black, furry tail. In his Demon form, Rin gains two horn-like blue flames floating above his head, long elven ears, and his prominent canine teeth become demonic fangs. His eyes change as well; his pupils become red and slitted, while his irises take on a jagged triangular shape and become a deeper shade of blue. The blue flames also blaze around other places of his body, mostly at the tip of his tail and on his shoulders, as well as his sword.