Kyojuro Rengoku/Relationships

Tanjiro Kamado
During their initial meeting at the Ubuyashiki Estate, Kyojuro develops a strong dislike for Tanjiro since he broke the Demon Slayer Corps rule of not protecting a Demon and such he rules in favor of killing Nezuko as well as in seeking punishment for Tanjiro. However, as the story progresses, he begins to take a liking towards Tanjiro after meeting him again on the Mugen train. The two boys develop a mutual respect for each other as fellow Demon Slayer Corps members, to the point where Kyojuro offers to make Tanjiro his Tsuguko. Tanjiro develops a strong admiration and affinity for Kyojuro, to the point where he calls him "Aniki" showing their brotherly bond. Tanjiro is greatly impressed by Kyojuro's swordsmanship and ability to smile on through the pain of fighting. Just before he dies, Kyojuro entrusts his will to Tanjiro, suggesting that he had grown very fond of the young Demon Slayer for the few hours they knew each other for. Soon, Kyojuro's hilt is passed down to Tanjiro by his younger brother Senjuro.

Nezuko Kamado
At first, Kyojuro didn't accept Nezuko to be in the corps since the rule of not protecting a Demon was broken. He rules in favor of killing Nezuko due to her being a potential threat because she is a Demon. After the fight aboard the Mugen Train, Kyojuro is grateful for Nezuko protecting the passengers on the train. As Kyojuro was dying, he told Tanjiro that he believes in Nezuko and that he accepts her as a member of the Demon Slayer Corps. He states that anyone that protects humans from demons is a rightful member of the Demon Slayer Corps.

Inosuke Hashibira
As with most new people he meets, Inosuke doesn't particularly like Kyojuro when he first meets him. However, when he sees Kyojuro protecting the people on the train and fighting Akaza, he grows to respect Kyojuro's strength and swordsmanship. After Kyojuro's death, Inosuke is the one to pick Tanjiro back up and remind him of the words Kyojuro had shared with them before he died and the fact that the Hashira believed in them.

Mitsuri Kanroji
Kyojuro was Mitsuri's mentor, and the two were very close. While training under him, Kyojuro was notably strict with her training but still showed patience with her. The two of them share a gluttonous side and enjoyed snacking on their breaks. Mitsuri derived her own unique Breathing Style, Love Breathing, from his Flame Breathing. She holds extreme gratitude towards Kyojuro for his guidance and kindness. Mitsuri was greatly shocked and saddened after she heard of his death.

Akaza
Kyojuro hates Akaza because of their contrasting beliefs; the Upper Rank believes that weak humans just get in the way of others and that their existences are worthless where Kyojuro believes the weak and valuable and should be protected by the strong. Akaza takes a liking to Kyojuro because he can sense that his battle spirit is strong, and offers for him to become a Demon, but Kyojuro says that he would never sacrifice the beauty of humanity for immortality.

Senjuro Rengoku
Senjuro is Kyojuro's younger brother. Kyojuro cares deeply for him and fills in the role of his mentor for Flame Breathing. According to Senjuro himself, he failed to master the technique due to his lack of skills so he gave up. However, Kyojuro appears to still be proud of him. He was deeply saddened and depressed after he had heard of his death.

Shinjuro Rengoku
Kyojuro's father and the former Flame Hashira. When Kyojuro was younger, he and his brother trained under their father and he described him as a passionate man. After the death of his wife and his retirement from the Demon Slayer Corp, their relationship grew distant. Even after Kyojuro succeeded him as the Flame Hashira, Shinjuro showed little care over the news and dismissed it. After his death, Shinjuro insulted his son in a drunken stupor and seemed to not care about his passing. Kyojuro on the other hand never stopped caring about him even after he became distant and his final message was for him to take care of himself and his body. After hearing this, Shinjuro came to regret his harsh words and cried in grief of his deceased son. During the final battle against Muzan, Shinjuro rejoined the Demon Slayers along with Tengen Uzui as the final line of defense protecting Kiriya Ubayashiki, vowing to not bring shame to the Rengoku family and Kyojuro's memories.

Ruka Rengoku
Kyojuro's mother who passed away from an illness when he was young. As seen in his memories of her, she was very stern towards him and at the same time warm and gentle towards him. She proved to be a big influence in his overall philosophy as she explained to him that he was born strong to protect the weak, and to never use such a gift for selfish gain. She deeply loved Kyojuro as she expressed gratitude in tears that she was blessed to have him as a child, someone born both strong, kind, and gentle. Kyojuro deeply cared for and loved her in return, as her words towards him gave him the final push to hold down Akaza in a final attempt to kill him despite his grievous wounds. In his final moments, Kyojuro envisioned his mother's spirit who expressed that he did well and she was greatly proud of him, allowing him to pass on with a smile on his face.