I know what eternity is. Eternity is human feeling. Only human feelings last forever... and are undying.
Kagaya Ubuyashiki (
Kagaya has light skin and black shoulder length hair. He has a curse mark that is slowly killing him that also makes his skin look as if it was rotting spreading down his face and covering his eyes making him unable to see, by the time of his death this curse had spread all over his body making moving nearly impossible. Muzan at Kagaya's death described him as having the smile of a Buddha.
He usually wears a black kimono with a long white haori with a pink and purple mist like pattern that starts around the lower back/waist.
Kagaya has a calm demeanor; showing genuine care about the members of the Demon Slayers, even considering them as his children. He is also able to handle criticism well, and is honest about his weaknesses; one being his inability to become a Demon Slayer despite being their main leader. In order to make up for this, he remembers every single member of the corps and visits the deceased members at their cemetery on a daily basis until he could no longer move due to the curse.
While he may seem lenient, he gives due consideration to reason; clear of any biases, shown when he willingly accepted the situation of Tanjiro and Nezuko (via a letter from Sakonji Urokodaki) and even defending their cause when there are others who thought otherwise. His manner of speaking, while generally fluid and gentle, is extremely tactful; using words and intonations in a way that the person he talks to would listen. His tactful and charismatic speech is even able to make the likes of the initially passive Muichiro Tokito and the impulsive Sanemi Shinazugawa listen to what he has to say without saying or conveying anything that would rile them up.
Towards his own kin, such as his children, Kagaya is rather strict due to the curse of their family. He nevertheless shows the same gentle aura and demeanor towards them.
Kagaya became the leader of the Demon Slayer Corps when he was only 4 years old. Kagaya first met Amane when he was 13 years old which was when she was 17. She was specifically selected by a priest to become Kagaya's wife in order to care for his medical needs, but he only agreed to the marriage on the condition that she cared for him on her own free will.
Foresight: In addition to his special voice, Kagaya (and the rest of the Ubuyashiki family) possess a heightened level of foresight that helps them avoid disastrous situations and amassed them a great amount of wealth and fortune. Due to this instinct, Kagaya accurately made several guesses about multiple things that were eventually proven to be true and accurate without him knowing any prior information, as seen when he accurately predicted that Muzan's only remaining weakness was the sun and that he could not be destroyed by decapitation, that the deaths of Gyutaro and Daki would send waves that would eventually see that the Upper Ranks of the Twelve Kizuki begin losing members for the first time in hundreds of years, and that Muzan will find him and bring about the final war between Demon Slayer Corps and the Twelve Kizuki during his last five days of life.
- Kagaya shares the same Japanese and English voice actors with Seijiro Kikuoka from Sword Art Online.
- The Japanese voice actor of Kagaya, Toshiyuki Morikawa, also voices the main antagonist Naraku from Inuyasha series. Ironically, in a manner, Naraku can be seen as a parallel version of Muzan (both of them are manipulative and want to achieve "perfection").
- As stated by Kagaya, the disease currently ailing him is the curse inflicted on his family due to them birthing the "Original Demon". The sickness itself is a genetic disorder passed down from generation to generation in their family, it has effectively left the Ubuyashiki family with weak bodies and a lifespan of less than 30 years.
- His first name contains the kanji for "Shine" (耀 Kagaya) and "How" (哉 Ya) the Ya in 耀 is not included and is instead replaced by the kanji 哉. His surname contains the kanji for "Bear" (産 Ubu), "House" (屋 Ya) and "Spread" (敷 Shiki)
- (To Tengen Uzui) "Tengen, the path you chose is a hard one. It is hard to reject the values you learned as a child. You must always fight yourself at the same time that you're fighting on the field of battle. But in spite of your many inner conflicts and contradictions...I trust you to always fight for me and to protect innocent lives. Thank you Tengen, you are a wonderful child."
- (To Mitsuri Kanroji) "Mitsuri you are especially beloved by the gods. Be proud of your strength. Those who speak ill of you fear your talent and are merely envious!"
- (To Sanemi Shinazugawa) "I'm sorry. I tried swinging a sword but it made my heart pound and I couldn't even do it ten times. I would have been like you if I could have. I wanted to be a strong swordsman and protect others' lives with my own body. But... it was impossible for me. I'm sorry to have to ask you to do such difficult tasks[...] If you are pawns... then I am a sacrificial piece too. And if a single piece, even one such as myself, who moves the Demon Slayer Corps, were to die, nothing would change. This is your first time at a gathering of the Hashira, so I think you misunderstand. I do not place myself higher than you or anything like that. But everyone just treats me that way. If that bothers you, you don't have to go along with it. Instead of worrying about that, defend the lives of others as a Hashira. That is my only request."
- (To Sanemi Shinazugawa about Masachika Kumeno) "Sanemi... all the children of the Demon Slayer Corps write their own wills. Strangely, the contents of those wills are mostly similar. Masachika's was the same. I have been thinking about giving it to you. Masachika thought of you like the younger brother he lost. He dreamed of a shining future. Just like my dream. A wish for loved ones to smile. To live happily until the day they die and to never have their lives cruelly threatened. Even if you can't be by their side. We want them to live. We want them to survive."
- (To Muichiro Tokito) "You mustn't be inflexible in your thinking, Muichiro. When you recover your confidence, you will get stronger."
- (To Muzan Kibutsuji) "And it's all because... I burn to defeat you, Muzan."
- Kimetsu no Yaiba Manga: Chapter 139 (Page 1).
- Kimetsu no Yaiba Manga: Chapter 47 (Page 19).
- Kimetsu no Yaiba Manga: Chapter 45 (Page 21).
- Kimetsu no Yaiba Manga: Chapter 46 (Page 5).
- Kimetsu no Yaiba Fanbook 2
- Kimetsu no Yaiba Manga: Chapter 47 (Page 15).
- Kimetsu no Yaiba Manga: Chapter 139.
- Kimetsu no Yaiba Manga: Chapter 138.
- Kimetsu no Yaiba Manga: Chapter 87 (Pages 9-10).
- Kimetsu no Yaiba Manga: Chapter 124 (Page 2).
- Kimetsu no Yaiba Manga: Chapter 168 (Pages 12-14).
- Kimetsu no Yaiba Manga: Chapter 168 (Pages 16-17).
- Kimetsu no Yaiba Manga: Chapter 118.
- Kimetsu no Yaiba Manga: Chapter 137 (Page 13).