Serpent Breathing: Obanai’s five forms

Obanai Iguro trusts no one. The lower half of his face hidden under a bandage, one yellow eye and one turquoise eye, he watches the other demon slayers warily, perched on a branch or leaning against a wall. His sword is just like him: a blade that ripples like a snake, and strikes where you do not expect it.

Here is where Serpent Breathing comes from, its five forms, the unique weapon it requires, and the story of the man who carries it. To place Serpent among the other breathing styles, our page on all the Demon Slayer breathing styles presents the fourteen known styles.

What is Serpent Breathing?

In Demon Slayer, Serpent Breathing, Hebi no Kokyū in Japanese, is a derived style. It was born from Water Breathing, one of the five basic styles that came from Sun Breathing. From Water, it keeps the fluidity, but turns it into something else: a twisting flexibility that goes around obstacles instead of through them.

Its attacks never come in a straight line. The blade snakes, coils, comes back from a blind spot. The opponent thinks they are parrying a blow, and the tip appears on the other side of their guard. It is a style of cunning and patience, which strikes like a snake: fast, at an angle, at the chosen moment.

Obanai is its only known user. Like most derived styles, it is tailored to one body and one weapon, and it is hard to see who else could practise it. Our article on Water Breathing presents the original style, and the one on the breathing tree shows the whole family.

The five forms of Serpent Breathing

The five Serpent forms bear names of snakes, fangs and constrictions. They appear during the final assault, in Muzan’s castle, where Obanai uses them against the most formidable demons in Demon Slayer.

The names are carefully chosen. “Ida”, in the first, refers in Japanese to something that winds and twists. Toguro, in the third, is the word for the coil a snake forms when wound around itself. The fourth shows two white snakes on screen, like two heads springing from the same body.

These forms express a philosophy of combat. Serpent does not face head-on: it waits, watches, looks for the gap, then bites. Obanai uses it with cold precision, never leaving himself open, which makes him one of the hardest fighters to hit in the Corps.

A blade and a snake

Obanai’s sword looks like no other. Its blade is wavy along its whole length, like a snake lying flat. It makes his cuts unpredictable: even when the opponent sees the movement, they do not know exactly where the blade will pass.

Obanai never really fights alone. Kaburamaru, a white snake with red eyes, stays coiled around his neck and shoulders at all times. He keeps watch, observes the surroundings and serves as the Hashira’s ally. The two have been inseparable since Obanai’s childhood, and Kaburamaru is probably the only being he trusts completely. The snake was already there in the cage where the boy waited to be devoured, and it was with him that he escaped. Since then, he has never left his side, to the point that the other Hashira cannot imagine Obanai without him.

This wavy blade comes as a replica, to display or carry in cosplay: four regular curves, black back, round green guard. It is filed in the katanas collection and the complete Obanai Iguro collection.

Obanai Iguro, the Serpent Hashira

Obanai grew up in a clan that lived in the service of a snake demon. In exchange for stolen riches, the family handed her its own newborns. Obanai, born with eyes of two colours, is set apart, locked up and fed to be devoured when the time comes. The demon slits his mouth so that it looks like hers, a mark he has hidden under a bandage ever since.

One day, he escapes. The demon pursues him, and the former Flame Hashira, Shinjuro Rengoku, saves him. But the whole clan pays for his escape: the demon massacres almost all of them. A survivor blames Obanai for their death. He grows up convinced that he is tainted by this clan’s blood, and deserves no happiness. Every demon he cuts down is, for him, a way of paying off a debt he believes can never be settled.

He becomes a demon slayer to redeem himself, and a Hashira through his own merit alone. But the shame never leaves him. It explains his harshness towards others, his contempt for those who weaken, and his mistrust of Tanjiro and Nezuko. Our portrait of Obanai Iguro, the Serpent Hashira tells his life in detail, and the one of Shinjuro Rengoku, the former Flame Hashira presents the man who saved him.

Obanai comes as a five-panel canvas, in black, white and grey: he occupies the central panel, sword raised, his white snake coiled around him. It is filed in the posters collection and among the Demon Slayer Corps products.

Obanai at the Hashira meeting

Demon Slayer viewers discover Obanai at the end of the first season, at the Hashira meeting. Lying on a branch, Kaburamaru around his neck, he demands the execution of Tanjiro and Nezuko with a chilling coldness. When Tanjiro struggles, he is the one who pins him to the ground with a simple press of the elbow, with no apparent effort.

This first appearance sums up the character: discreet strength, formidable precision and absolute mistrust of anything to do with demons. For Obanai, who grew up in the service of a female demon, sparing Nezuko amounts to betraying everyone the demons have devoured. He will take a long time to change his mind, and only after seeing the girl protect humans.

Our article on Demon Slayer season 1 tells of this meeting, where each Hashira introduces themselves for the first time.

What Serpent demands of the fighter

In Demon Slayer, each breathing style fits a body and a character. Serpent first demands surgical precision. The wavy blade does not forgive approximation: you have to know exactly where each curve will pass, and place the blow in the opponent’s gap. Obanai, small and light, makes up for his build with this exactness.

It also demands patience. Serpent does not attack blindly: it watches, waits for the moment the opponent leaves themselves open, then strikes in one go. It is not a style of fiery impulse, like Flame or Wind, but of restraint and calculation.

Like all breathing styles, it rests finally on Total Concentration Breathing, which the Hashira maintain day and night. Our article on Total Concentration Breathing explains this common foundation, and our page on the Demon Slayer Hashira presents Obanai among his peers.

Serpent in the Hashira Training

In season 4 of Demon Slayer, Obanai leads a stage of the Hashira Training. His test is cruel: the demon slayers must face him in a hall where other pupils, those who failed, are tied to posts and serve as obstacles. You have to strike without touching the prisoners, slipping between them.

The exercise is not gratuitous. It teaches perfect control of the blade, striking accurately in a cluttered space, exactly what Serpent demands. Obanai is particularly hard on Tanjiro, whom he considers too close to Mitsuri. The boy nevertheless ends up passing the test, through sheer persistence, and Obanai lets him move on to the next stage without a word of praise.

The anime also gave the Serpent Hashira a scene the manga does not contain. Season 4 opens with a night mission in which Obanai and Sanemi Shinazugawa fight together. Our article on the differences between the anime and the manga tells of this opening, and the one on season 4 and the Hashira Training details each stage.

Serpent on screen

In the Demon Slayer anime, Serpent Breathing can be recognised by its winding purple trails, which twist in the air like moving snakes. The studio ufotable gives it a scaly texture and curves that seem alive, very different from the waves of Water from which it descends.

The fourth form, Twin-Headed Reptile, offers its most striking image: two white snakes spring up on either side of the opponent, like Kaburamaru. For anime viewers, the Serpent Hashira still remains discreet, as his big fights belong to the Infinity Castle. Our article on ufotable, the studio behind the animation tells how these effects take shape, and the one on the Infinity Castle sequel takes stock of the films to come.

Obanai and Mitsuri

Obanai loves Mitsuri Kanroji, the Love Hashira. He never tells her, but he writes to her, gives her striped stockings, and never takes his eyes off her during the Hashira meetings. With her alone, his mistrust falls away. She is the only person who does not look at him like a monster. When she tells him about her missions, he listens without interrupting, which he does for no one else.

Our pop figure shows Obanai in a moment of calm, seated on a pine branch, Kaburamaru coiled along his arm, its head turned towards him. It is filed in the pop figures collection.

Yet he stays silent, convinced that his blood makes him unworthy of her. He waits for the end of the war, for Muzan’s death, to dare speak to her. Our article on Love Breathing presents Mitsuri and her style.

This part of their story ends in Muzan’s castle, which the anime has not yet adapted. The two Hashira fight side by side to the very end, and make each other a promise for another life. In Demon Slayer, few scenes have moved readers so much.

Serpent in the Infinity Castle

This part reveals elements of the Infinity Castle arc that the anime has not yet adapted.

In the castle, Obanai cuts down a horde of demons with a single fifth form, then joins the Hashira facing Muzan himself. There he unleashes his most powerful forms, and his blade turns red under the strain, a crimson blade that slows the demon’s regeneration. Wounded in the eyes, he keeps fighting, guided by Kaburamaru.

The fight costs him his life, but he helps hold Muzan until dawn. To read this ending, our article on the chapter to read after the anime tells you where to pick up, and our page on the demons and the Twelve Kizuki presents Muzan.