Ryū (龍, Ryū) is a Hunter-nin from Kirigakure as well as the brother of Raizen, one of the Seven Ninja Swordsmen of the Mist. Himself a highly skilled swordsman, he has received extensive training in the ways of the blade from his brother and was also a swordsman apprentice, serving on a number of missions with his brother as an affiliated member of the Seven Swordsmen. He is capable of molding an unique type of chakra called as Dark Chakra which allows him to execute a number of rather unique techniques. This, along with his trademark dark clothing and the black sword that he carries have earned him the title of the Shogun of the Dark (暗いの将軍, Kurai no Shōgun).
A fact hidden from most is that as a child Ryū was kidnapped by members of the Jashin cult who repeatedly experimented on him till he was rescued by Raizen. These experiments are the reason he is able to use Dark Chakra and can use one of their techniques, Curse Technique: Eternal Damnation. As Raizen killed all the Jashinists who had captured Ryū and destroyed their equipment and data, Ryū, being the only subject who successfully assimilated to the technique, was the only surviving being with access to the completed technique. As a result the followers of Jashin have hunted him ever since he escaped in order to retrieve the technique from his body.
Ryū is a tall, lean person with peach skin and brown eyes. The most striking feature anout his appearance is his spiky orange hair, a trait that has caused him to face a great deal of ridicule and even animosity from others. He is normally dressed in clothes similar to those worn by his brother, consists of a white shitagi, a black kosode, a black hakama, a white hakama-himo, white tabi, and waraji. Below all this his torso and arms are tightly wrapped in plain white bandages.
As a hunter-nin he wears a mask which is slightly unique in its design as compared to the ones worn by most of his comrades. His mask resembles a menacing skull and is white in color with four thick stripes emerging outwards from the widened eye-holes of his mask and disappearing into both sides of the lower jaw and traveling past the very top of the mask itself.
Ryū's personality is that of a stereotypical smart-aleck teenager with a lightning-fast wit and a sarcastic and deadpan sense of humor. He possesses a happy go lucky sort of attitude and always has a witty comeback and can out-talk almost anyone. As a child he was always in the center of attention and at the heart of numerous mischievous activities, a typically goofy, optimistic and exceedingly hyperactive troublemaker. But due to his quick mind and sharp tongue he was hardly ever the one blamed. His best friend Kenshin was always with him in these activities and often the one who got blamed. But in these situations Ryū always stepped forward as he hated letting Kenshin take the blame for his misdeeds. But these exceptions were only made if Kenshin was involved and if anyone else got caught for his misdeeds then Ryū would laugh at and tease the one who had to take the blame for his actions. Though he pulled pranks on almost everyone and loved seeing them get into trouble, he was always the first one to go to their aid if they were in serious trouble. Due to this though nearly everyone was irritated by his numerous pranks, he was still liked by everyone and made numerous friends. He will always stand up for his friends and will defend them no matter what the situation. This was shown when he defended Kenshin when he was exiled from the village and went on believing his innocence even when all things proved otherwise. Since Kenshin's banishment Ryū has become a little more serious and contemplative.
Like his brother he is a very honorable man and possesses tremendous strength of character. He refuses to give up when he believes something is wrong and will even break a rule to do what he thinks is right. Despite being a prankster as a child, his moral compass has always pointed in the right direction even if it sometimes sways a little.
Something that has not changed his childhood are his fiery attitude and headstrong ways. His fierceness and determination along with his highly dependable nature make him a born leader and his leadership has on numerous occasions allowed his followers to get through even the toughest of battles. Be it in combat or showing diplomatic skills, he has repeatedly shown himself to be a natural leader, leading Kirigakure's forces in a number of conflicts with great skill. Despite his great power he does not rely on fear to make others follow him. He leads by example and does not push his subordinates into any situation he himself would not be willing to go through.
- Kurai (暗い, The Dark One): Ryū's signature weapon, Karui is a daitō (Japanese long sword) with a jet black blade.
- Senbon: During his training upon joining the ANBU and subsequently the Hunter-nin, Ryū gained an extensive knowledge of the human physiology and how to effectively use senbons to target acupuncture points and incapacitate an opponent. Along with normal ones he also carries a number of senbon with him whose tips have been been poisoned. He can launch them from a wide range of angels and from a decent distance from his target.
Ryū is a highly proficient swordsman and is in his own way a master of the blade. The greatest strength of his swordsmanship is his ability to adapt to varying situations and as such he has even trained himself to become ambidextrous so as to make himself more versatile. His fighting style consists of graceful and quick movements and he prefers finishing his fights quickly rather than dragging them on. Not one to make use of, he tries to deal accurate blows and perform quick maneuvers. He is capable of keeping track of multiple opponents or a single opponent with multiple blades and effectively withstanding their attacks.
- "Ryū" means "dragon" in Japanese.