Hinokami Kagura, also known as Sun Breathing, is easily one of the strongest Breathing Styles in the series by a wide margin.
Not only is Sun Breathing the first and strongest Style, but the Thirteenth Form is an amalgamation of the preceding twelve forms. In other words, this technique is twelve other techniques executed in a perfect, final sequence.
Apart from all the Five Main Breathing Techniques, Moon Breathing is also branched out of Sun Breathing. Kokushibo, Upper-Rank One, is the only Known user of this technique. Despite being inferior to Sun Breathing, it is stronger than other Breathing Techniques.
Tanjiro makes use of Water Breathing for most of the series. Taught to him by Sakonji during his training in the mountains, it is one of the five main styles derived from Sun Breathing.
Breath of the Sun
It's the oldest and most powerful breathing style that was used to develop the Flame, Water, Moon, Thunder, Stone, and Wind Breathing techniques that demon slayers use to this day. It mimics the intensity and versatility of the sun, lessening a demon's ability to regenerate.
What yogis refer to as Moon Breath or Chandra Bhedana involves breathing in through your left nostril only. The left side of your body is thought to be associated with the nervous system, and so Chandra Bhedana has been traditionally used to calm it down and promote sleep.
Moon Breathing is the demonic form of the primal Sun Breathing in Demon Slayer anime and manga. Developed by Kokushibo, aka Michikatsu Tsugikuni, this is the second most powerful breathing technique in the series that no human can use. Moreover, it also has more forms than any other type of breathing.
It is possible for a swordsman to use more than one Breathing Style technique at a time, allowing the user to take advantage of the advantageous aspects of both techniques. Tanjiro Kamado, for example, can use both the Water Breathing and Sun Breathing styles simultaneously.
Over the course of the series, Tanijiro unlocks multiple breathing styles, but only two have been shown in the anime so far. This list contains all the styles that Tanjiro has performed in the anime and the different techniques classed under them.
Thunder Breathing is one such technique that Zenitsu has used to great effect in the series. Of course, Zenitsu is only the master of the first form, but it goes without saying that the other techniques of Thunder Breathing will also be awe-inspiring to witness in Demon Slayer.
Thirteenth Form of Sun Breathing in Demon Slayer
It involves a combination of all existing Sun breathing techniques — but performed in a consecutive manner. This technique's primary purpose is to slash all the twelve vital organs of a demon. Each form targets a specific organ. Tanjiro only used it once in the manga.
When it comes to pure strength, Shinobu Kocho is the weakest Hashira in Demon Slayer. She doesn't even have enough strength to decapitate a demon's head and she makes up for it by injecting poison into the demons.
Gyomei Himejima, the Stone Hashira, is the strongest Hashira in the Demon Slayer corps in terms of strength and swordsmanship.
The only known Demon Slayer who is capable enough to have two Breathing Styles at his disposal is Tanjiro Kamado.
Yoriichi Tsugikuni is the creator of the Sun Breathing style and is also the strongest demon slayer that has ever lived. He existed nearly 500 years prior to the events of Demon Slayer and struck fear into the hearts of every demon he came across.
Sixth Form: Whirlpool
While fighting underwater, Tanjiro demonstrates the true power of the sixth form by creating a literal whirlpool that pulled two swamp demons directly into his blade. When combined with the footwork of the third form, this ability is able to create a whirlpool effect on land as well.
The fifth form accomplished exactly that. Called the Blessed Rain After the Drought, it's an attack meant to decapitate enemies without causing any pain, which allows enemies who have surrendered to die a graceful death without feeling any unnecessary pain.
After the deaths of Daki and Gyutaro, Kaigaku was promoted to become Upper Moon Six of the Twelve Demon Moons due to his power and confronted Zenitsu as a rematch he always desired.
Initially, Tanjiro's accuracy and strength were not up to the mark, which is why Muzan was able to avoid his attacks. However, Tanjiro accurately performed the thirteenth form and inflicted a ton of damage on the Demon King.
It seems that Tanjiro still has a long way to go to master the Water Breathing technique. Giyu, on the other hand, as the current Water Hashira, has complete mastery over all 10 forms of Water breathing, as well as an 11th form that he created himself.
When Tanjiro first got his Nichirin Sword on Demon Slayer, and it changed color to match the personality of its user like all Nichirin weapons do, many fans were surprised that Tanjiro's katana turned black.
Some of the characters who have faced Yoriichi and survived
This happened due to a treatment that had gone wrong. While he was being treated, Muzan killed the doctor because he was not able to observe any results.
Fourth Form: Burning Bones, Summer Sun
Unlike the two horizontal slashes of the Raging Sun, this technique allows for a circular slash that completely covers the area around the user. This makes Burning Bones, Summer Sun a perfect move to both dish out some pain and defend from blows too.
Known Techniques. As Kokushibo lived for centuries continuously improving his swordsmanship through his Moon Breathing Breathing Style, eventually developing 16 different techniques at least by the time of the Infinity Castle Arc.