We will discuss about Kyojuro Rengoku’s backstory from Demon Slayer: Kimetsu No Yaiba in this blog post.
Rengoku was the former Flame Hashira in the Demon Slayer Corps. He was one of the most skilled and fan-favourite Demon Slayers in the series. Rengoku gained popularity in the Mugen Train Arc while he was fighting against the Upper Rank Three, Akaza.
Kyojuro Rengoku was very passionate about his job as a Hashira, and he often seemed like a happy-go-lucky oddball.
He was friendly, had a good heart, and had fantastic swordsmanship and technique that came from hard work and discipline. He was a good warrior who stuck to the morals and rules that his mother taught him when he was young.

His most important belief was that people born strong have a duty to protect those weak.
Here, we will see Rengoku’s backstory in Demon Slayer: Kimetsu no Yaiba.
Kyojuro Rengoku Backstory – As a Child
Kyojuro Rengoku was the eldest son of Shinjuro Rengoku.
His father had been a member of the Demon Slayer Corps and held the position of Flame Hashira until he suddenly decided to resign. The reason why Flame hashira suddenly resigned from his responsibilities is still unknown.

Mentorless Kyojuro and Losing his Mother
He was training Kyujuro and his younger brother at the time. But after giving up his position as the Hashira, he stopped their swords and flame-breathing style training.
His mother, Ruka Rengoku, fought a long and ultimately fruitless battle against an ailment. She was not able to win that battle, and nothing could heal her from that illness. She passed away as a result.

This happened sometime after Kyojuro’s younger brother, Senjuro, was born.
Kyojuro’s Love For His Family
Kyojuro also loved his family very much.
Even though his father Shinjuro Rengoku, was getting more and more angry and uninterested in Kyojuro, Kyojuro still had a lot of respect for and worry about his father. He has a lot of faith in his younger brother, Senjuro Rengoku, and is always happy and upbeat about him.
He also wants the best for himself, no matter what the situation is. Rengoku always had optimism in everything he did. He knew that he could change everything about his life from his positive thoughts.

Even more proof of this is that before he died, he told his father and younger brother to “take care of your body” and “follow your dreams no matter what.”
The Kyojuro school of thought also says that a person’s dedication to achieving their goals and good intentions are not wasted, even if they don’t have exceptional talent.
Kyojuro Rengoku Backstory – Demon Slayer and Hashira
Kyojuro was already known to be a great fighter before he took over for his father.
He took revenge for the deaths of the nine Demon Slayers who were killed by the Flute Demon by himself.
Later, he beat Lower Rank Two Hairo by himself. Before he died, Hairo praised his swordsmanship.
Shinjuro Rengoku, his father, said that after he stopped teaching his son, Kyojuro trained himself to become a Hashira by reading only three volumes of the guidebook for the Flame Breathing style.
Even demons as strong as Upper Rank Three, Akaza, and the fourth-strongest known demon, praised Kyojuro’s strength. Akaza even offered to turn Kyojuro into a demon so he could go beyond his human limits and become stronger, which is something he only did for swordsmen whose skills he thought were at their best.

Final Thoughts – Kyojuro Rengoku Backstory
Kyojuro was a member of the Rengoku family, which has a long history of strong swordsmen and Flame Hashira. This gives Kyojuro an advantage when it comes to learning and improving his sword skills.
His extraordinary skill with a sword has been shown many times throughout the series.
Kyojuro learned the Flame Breathing Style from the previous Flame Hashira, Shinjuro Rengoku, and then mastered it by reading the instruction books left behind by previous Flame Hashira in the Rengoku Family.
As the Flame Hashira, Kyojuro is the best Flame Breather of his generation. He got so good at fighting with this Breathing Style that he was able to beat Hairo, a former Lower Rank Two, on his own and later hold his own against Akaza, an Upper Rank Three.