Flame Breathing: the Rengoku family’s forms

When Kyojuro Rengoku draws his sword, the carriage catches fire. The flames burn nothing: they show the strength he puts into every blow. With him, Flame Breathing became the breathing style Demon Slayer viewers love most, that of a hero who smiles to the very end.

Here is where this breathing style comes from, its nine forms, the family that has carried it for centuries, and what became of it after the night of the Mugen Train. To place it among the other breathing styles, our page on all the Demon Slayer breathing styles presents the fourteen known styles.

What is Flame Breathing?

In Demon Slayer, Flame Breathing, Honō no Kokyū in Japanese, is one of the five basic styles, with Water, Wind, Stone and Thunder. Like them, it descends from Yoriichi Tsugikuni’s Sun Breathing, versions of which he taught adapted to each of his pupils.

Flame stakes everything on power and commitment. Its forms move forward, strike head-on, and leave little room for dodging. Where Water adapts to the opponent, Flame crushes them with its will. It is a style for fighters who do not back down.

It is also one of the oldest in the Corps. Kyojuro Rengoku explains it to Tanjiro himself: the Demon Slayer Corps has always had a Flame Hashira and a Water Hashira. The two styles answer each other, one all fire, the other all flexibility. Our article on Water Breathing presents its twin, and the one on the breathing tree shows the whole family.

The nine forms of Flame Breathing

Flame Breathing has nine forms, but Demon Slayer only names six, all shown by Kyojuro. The sixth, seventh and eighth never appear on screen or in the manga.

The first form bears a poetic name. Shiranui refers to the mysterious fires seen at night out at sea, off Kyūshū, which nobody can explain. The ninth bears the family’s very name: Rengoku, purgatory.

The forms follow a simple logic: you swoop on the enemy, rise, bring down, sweep, then strike with all your strength. There is something of Kyojuro’s character in this sequence, frank, direct, straightforward.

What Flame demands of the fighter

Each basic breathing style corresponds to a type of body and character. Thunder wants legs able to explode in a fraction of a second, Stone extraordinary strength and resilience, Wind constant aggression. Flame, for its part, demands above all endurance and courage: its forms are delivered head-on, at close quarters, holding nothing back.

It is a style for protecting. The fourth form, Blooming Flame Undulation, sweeps a wide space in front of the fighter so that nothing gets past behind him. It is no coincidence that Kyojuro, on the train, takes charge of five carriages on his own: Flame is made for holding a line and covering the others.

It also demands perfect breathing. Like all the Hashira, Kyojuro maintains Total Concentration Breathing day and night, and that is what lets him stay on his feet long after a wound that would have killed any human. Our article on Total Concentration Breathing explains this foundation common to all breathing styles.

The Rengoku family, keeper of the Flame

In Demon Slayer, Flame is a family affair. The Rengoku have passed it down from father to son for generations, and several of them have been Flame Hashira. Their house even keeps a record of former Flame Hashira, handed down through the ages.

Shinjuro, the father, was Flame Hashira before his son. One day, he stopped fighting. The death of his wife, Ruka, broke him, and reading the family record, which speaks of Sun Breathing and its superiority, convinced him that all the Rengoku family’s efforts led nowhere. He now spends his days drinking, and greets his sons with contempt.

Yet it was in this house that Kyojuro grew up, learning on his own from his father’s books. Our article on Shinjuro Rengoku, Kyojuro’s father tells of the former Hashira’s fall.

The family symbol lies in the guard of Kyojuro’s sword, an orange flame closed around a yellow heart. You will find it on our katana replica, to display or carry in cosplay, in the katanas collection.

The heart of Flame is a lesson from his mother. Before dying of illness, Ruka explained to Kyojuro why he was born strong: those who receive more strength than others have a duty to protect the weakest. Kyojuro made this sentence the rule of his life, and it is to it that he turns at dawn, in his last moments.

Kyojuro Rengoku and the night of the Mugen Train

On the Mugen Train, Kyojuro protects five carriages of sleeping passengers on his own, while Tanjiro, Zenitsu, Inosuke and Nezuko share the others. No one dies. Then, at daybreak, Akaza arrives, Upper Moon Three.

The fight pits two masters against each other. Akaza offers Kyojuro the chance to become a demon so they can fight forever; Kyojuro refuses. He strings together the Flame forms, Flame Tiger included, then stakes everything on the ninth, Rengoku. The assault is not enough: Akaza’s fist pierces him. But Kyojuro holds him until the sun rises, and the demon has to flee.

Before dying, Kyojuro speaks to Tanjiro. He asks him to protect Nezuko, to hold his head high, and leaves him a sentence that has become famous: “Kokoro wo moyase”, set your heart ablaze. Our portrait of Kyojuro Rengoku, the Flame Hashira tells his life, and the one of Akaza, Upper Moon Three presents his opponent.

You can keep this ninth form close: our pop figure shows Kyojuro sword in hand, a fire dragon’s head bursting from the flames beside him. It is filed in the complete Kyojuro Rengoku collection and in the pop figures collection.

Senjuro and the flame guard

Kyojuro’s little brother, Senjuro, should have inherited Flame in his turn. But when he took up his Nichirin sword, the blade did not change colour, a sign that he did not have what it takes to be a demon slayer. He chose another, more discreet path, without giving up on helping those who fight. He looks after the house and his father, and keeps his brother’s memory with a gentleness Shinjuro has lost.

When Tanjiro comes to announce Kyojuro’s death, Senjuro welcomes him with gratitude, then gives him his brother’s flame-shaped sword guard. Tanjiro has it fitted to his new blade in the Swordsmith Village. The Rengoku Flame thus keeps fighting, in another form, alongside Tanjiro.

This bond between the two brothers is shown on our shower curtain: Kyojuro and Senjuro side by side on a background of red maple leaves. It is filed in the curtains collection.

Flame on screen

Flame Breathing owes a great deal to the animation. The studio ufotable gave each of Kyojuro’s forms its columns of golden fire, its sparks and its light catching his face at an angle. The ninth form takes the shape of a blazing charge that crosses the screen, and the dawn scene facing Akaza remains one of the most striking in the whole series.

The Mugen Train film, released in 2020, became the highest-grossing film in Japanese history, and Kyojuro’s Flame has a lot to do with it. The ending song, Homura, “flame”, sung by LiSA, extends the emotion of the final fight. Our article on the Demon Slayer theme songs tells of this song, and the one on the Mugen Train, as a film or a series presents the brand-new episode devoted to Kyojuro before his mission.

Love Breathing, born from Flame

Flame gave birth to one known breathing style: Love, that of Mitsuri Kanroji. Before becoming a Hashira, Mitsuri was Kyojuro’s disciple, and she learned Flame Breathing from him. Her extraordinary body and her flexibility then pushed her to create her own style, with a thin blade as flexible as a whip.

In Love you find the warmth of Flame, but without its stiffness: where Kyojuro moves straight ahead, Mitsuri ripples. Our article on Love Breathing tells of this style, and our portrait of Mitsuri Kanroji, the Love Hashira looks back at her youth.

This lineage gives a special meaning to the bond between Kyojuro and Mitsuri. His death takes her former master from her. In Demon Slayer, breathing styles are not passed on only through training: they also pass through the bonds between people.

Flame and the Dance of the Fire God

At the start of the Mugen Train, Tanjiro asks Kyojuro a question: does he know anything about the Dance of the Fire God, which his father performed at New Year? Kyojuro knows nothing. For Tanjiro, who saw fire in this dance, the Flame Hashira seemed the obvious person to ask.

The answer will come later, from Shinjuro himself. Seeing Tanjiro’s earrings, the former Hashira understands that before him stands an heir of Sun Breathing, the origin of all breathing styles, Flame included. The Dance of the Fire God is not a variant of Flame: it is its source.

The manga actually keeps the confusion going. The name of the dance, Hinokami, is written there in katakana, a script that says nothing about the meaning. “Hi” can be read as fire, but also as sun. The reader long believes in a fire god, a cousin of Flame, before understanding that it had been the sun god from the start. Flame Breathing was only a reflection of this older light.

Our article on the Dance of the Fire God tells of this breathing, and our page on the Demon Slayer Hashira presents the other keepers of the breathing styles. For Kyojuro’s place facing the demons, our page on the demons and the Twelve Kizuki presents Akaza and the other Moons.