1. Home
  2. Otapedia
  3. Anime
  4. Kimetsu no Yaiba (Demon Slayer)
  5. Rui - Kimetsu no Yaiba (Demon Slayer)

OtapediaRui - Kimetsu no Yaiba (Demon Slayer)

Rui (累) was born in a very weak and frail human body many years ago, but reborn as a Demon he is a member of the Twelve Demon Moons and holder of the lower moon five. He is the founder of his Spider Demon Family and assumes the family's youngest position as a child. His body was so frail when he was a child, that it was impossible for him to move. He took the deal given by Muzan Kibutsuji to become a Demon, in order to get a strong body. His real family included his father, mother, and himself. One day after the parents saw that Rui wanted to kill and eat other people, they decided to commit suicide in order to atone for their sins. Rui, though, killed his parents at the last minute but at the same time shattered the only real family connection he had. He meets Tanjiro Kamado in quest of a true family relationship with a view to taking Nezuko. His Japanese voice actor is Koki Uchiyama, and makes his anime debut on Episode 15.


Rui has the appearance of a young boy, his skin is pale white with red dots all over his face. His hair is styled in a spider-like haircut with bangs that cover his left eye, in the same color as his skin. The sclera of his eyes are red, and his irises are pale blue but notably on his left eye, he has the kanji for the number five signifying his rank. He wears a traditional looking Yukata that has a cobweb pattern on the sleeves and a black obi wrapped around the waist, matching with the rest of his “family”.


Rui is a person who wanted a stable family to have the same strong bonds. He longs for the family connection he'd dreamed at the expense of repeated abuse in his family. His power is the greatest in his family and he uses it to torment his kin, binding them to be burnt by the sun if they go against his wishes. Because of his incredible strength he behaves almighty, and he is conscious of his influence. Although he is incredibly cruel and arrogant, he is receptive to the language he hears towards him. As he sees Nezuko Kamado sacrificing herself to save Tanjiro, he displays emotional instability, and becomes obsessed with the idea of forming a relationship with her.


Rui was born several years ago with a fragile, delicate and easily exhausted human body that even the simple task of walking and breathing was hard for him to do, forcing him to spend a majority of his life stuck within his home being cared for by his mother and father who, given his frailty, loved him profoundly and respected him. One night, Muzan Kibutsuji confronted Rui, who then tried to "rescue" him and converted him into a Demon.

Now possessing a strong body Rui was finally able to move about freely for the first time bringing joy and happiness to his parents. It did not last, though, as he was now a Demon Rui needing to get nourishment by eating humans, which further led him to kill a human inside his house. His parents then encountered this gruesome scene that was instantly horrified by their son's wrongdoing. That night, his father and mother decided that Rui had to be punished and attempted to kill him in his sleep so he couldn't do anything more like that in the future. His father then managed to sneak on him with a knife and told him not to worry, because he was already planning to kill himself as his mother sobbed and wept outside his room.

However Rui awoke and in anger for their attempt on his life, killed them both instead in self-defense, rationalizing that his true parents would never try and kill him and thus considered them to be faked in denial. Nonetheless, as his mother lay dying, Rui overheard her regretfully apologizing to Rui for not being able to give him a healthy body until she died. Which then led him to remember his father's last words, suggesting that by sacrificing himself he and his wife would carry Rui to the afterlife, lead him to realize that his parents always cherished him and only sought to prevent him from being a monster.

Rui relied on the falsehood that his connection to his family was false. When he received encouraging words from Muzan, who rejected his original argument that they couldn't really be his relatives because he didn't accept his status as a Demon and convinced him to actually look for a new one.


  • Demon Abilities - He received a larger amount of blood from Muzan Kibutsuji which allows him to possess incredible amounts of power. His body is incredibly durable and hard to cut, surpassing the threads he creates. Being easily able to physically overpower his foes by simple actions like kicking, displays his enhanced strength. As one of the Twelve Demon Moons, Rui possesses powerful regeneration, where after getting slashed shows no visible pain and is healed immediately.
  • Cell Manipulation - Rui is able to create threads using his cells for offense and defense. The sharpness and durability is powerful enough to break Tanjiro’s Nichirin blade easily. He also has the ability to change the physical appearance of other Demons who consume his blood. Altering the appearance of his “Older sister” to match his own, which he did with the rest of his family.
  • Blood Demon Arts - At full strength, he pumps his blood into his threads increasing the sharpness and cutting ability. He is able to use techniques involving these threads such as creating a prison, or cage around the target for offensive purposes.


Official English Website
Official Website
Official Twitter

TOM Shop

Kimetsu no Yaiba (Demon Slayer)