Sound Breathing is a Breathing Style that mimics sound, specifically its disorientating loudness, and replicates it with the user's movements, techniques and abilities. Most, if not all, known techniques and forms utilize explosives to deal massive amounts of damage while making use of extremely fast movements similar to how fast sound travels as well as the user's sense of hearing. Users of Sound Breathing also visualize themselves seemingly generating and manipulating loud sounds and explosives when unleashing its techniques.
The only known user, Tengen Uzui uses a technique developed using his superhuman sense of hearing called Musical Score (譜面,Fumen?)[1], which involves Tengen reading his opponents' movements and deconstructing them into sound by analyzing the rhythm of their movements. Through this, he is able to take advantage of their openings to much greater effect by striking in a way similar to making the beat to a song. In conjunction with this, he uses small but powerful anti-demon bombs that are capable of damaging the bodies of Upper Rank demons.
Since this combat style was presumably created by Tengen, it can only be used with a specific set of weaponry, which is two gigantic nunchucks-like Nichirin Cleavers, which each have a notch in the sharp ends of their blades and are held together at the hilt by a metal chain. His swords are said to have large amounts of explosive power, and it is stated that, until Tengen's fight with UpperRank Six, no demon had ever survived a single blow from them.
Sound Breathing has 5 techniques and forms at minimum, of which 3 were demonstrated.
First Form: Roar (壱ノ型轟,Ichi no kata: Todoroki?)[2] - The user lifts their twin swords above their head and slams them down with great force, causing a loud sound resembling thunder as a result.
Fourth Form: Constant Resounding Slashes (肆ノ型響斬無間,Shi no kata: Kyōzan Muken?)[3] - The user holds their twin swords apart and spins them rapidly around themselves, enabling the blades to destroy anything it makes contact with for powerful defensive capabilities around the user.
Fifth Form: String Performance (伍ノ型鳴弦奏々,Go no kata: Meigen Sōsō?)[4] - The user holds the chain of their twin swords and rotates the blades at high speed while charging forward. The spin of the blades without changing grip allows for continual slashes while still being in motion.
Game Exclusive Techniques[]
Fourth Form: Constant Resounding Slashes, Glitz and Glamour (肆ノ型響斬無間・絢爛,Shi no kata: Kyōzan Muken - Kenran?)[5] - A more offensive version of Constant Resounding Slashes notable for it's usage of explosives and collaboration with the Ninju mice. The user slams their twin swords to the ground in a move similar to Roar, but with enough force and with the usage of explosive beads to blast the opponent into the air in a large explosion. As they fall back to the ground, the user executes Constant Resounding Slashes catching them in a barrage of slashes, before tossing even more explosive beads at them. The Ninju then throw in a comically large bead with their likeness on it. The user cuts into the large bead with one of their swords, causing a chain reaction which detonates the smaller beads, catching the opponent in the crossfire.
Fifth Form: String Performance, Bursting Bloom (伍ノ型鳴弦奏々・爆華,Go no kata: Meigen Sōsō - Bakka?)[6] - The user engages at their opponent unleashing a flurry of rotating slashes and chops with their swords. The final hit launches the opponent high in the air, making the user toss a plethora of explosive beads while throwing their chained swords in a boomerang-like style cutting all the beads to detonate them.
Rising Kick (打ち上げ蹴り,Uchiage Geri?)[7] - The user takes a forward front-step followed by a high-rising side-kick launching their opponent into the air.
TBA[5] - A collaboration between a Beast Breathing user and a Sound Breathing user. After both charging and kicking their opponent back, the Sound Breather proclaims that the Musical Score is completed and rushes forwards using String Performance. The Beast Breather then joins the fray and the two dual wielders relentlessly slash their opponent from multiple directions and angles. They then leap in the air before the Sound Breather takes out their explosive beads. Both users cut and detonate them, using the explosions to blast themselves down towards their target, creating another powerful explosion when they land.
Fervent Fulmination (爆炎響動,Bakuron Kyōdō?)[5] - A collaboration between a Flame Breathing user and a Sound Breathing user. Both charge at their opponent and knock them back, and when they catch up, both coordinate their attacks to send their opponent in each other's direction. The Sound Breather then hurls explosive beads at their opponent after they are sent airborne, and is then joined by the Flame Breather who executes Flame Tiger as they jump upward. When they make contact with the target, the result is them being attacked by the blades of both Flame and Sound Breathing users, as well as being caught in the explosions from the latter's beads. The attack culminates with large fireworks as the users land on the ground.
Art Is An Explosion! (芸術は爆発だ！,Geijutsu wa Bakuhatsuda!?)[5] - A technique exclusive to the Kimetsu Academy version of Tengen Uzui. The school's Art teacher orders his opponent to strike a pose so he could paint a portrait of them. However, he gets angered by their lack of panache and hurls a lit stick of dynamite at them, becoming much more satsifed after the explosion.
While Insect Breathing is the Breathing Style with the least known minimum forms, Sound Breathing is the Breathing Style with the least known forms demonstrated at only 3 out 5 demonstrated.
Whenever the Sound Breathing user performs their techniques, they visualizing themselves creating amber and turquoise slashes while generating colorful explosions that mimics fireworks.
Demons' opinion on being slayed by Sound Breathing and its wielder is as follows:[8]
"It was a really clean cut." - Demon A
"He's brawny, but quiet and agile." - Demon B
"Practically silent!" - Demon C
"He precisely calibrated his every movement." - Gyutaro
"I thought 'Ninjas are real!' I hate that guy!" - Ume
