Yoriichi Tsugikuni: Origin, Powers, Sun Breathing, and Muzan Fight Explained

 As we all know, ufotable has announced 3 Demon Slayer Movies which will cover the story's final arc, releasing in 2025, 2027, 2029, respectively. In the final Arc, we will be seeing the final battle of the Demon Slayer Corps against the King of Demons, "Kibutsuji Muzan" and his Forces. In this Battle, we will witness the true power of each character, and we will get information on some Characters from the past as well. There are many Characters in the series whose backgrounds are still Unknown, and one of those characters is Yorichii Tsugikuni. Today, Senpai will write about Yorichii Tsugikuni, also known as the strongest demon slayer, and his impact on the Story.

Who Is Yoriichi Tsugikuni? and Transparent World and Demon Slayer Mark

Yorichii was a Man born around the 1400s and was the first person to use breathing style. Yorichii was born with the ability of the Transparent World and a Demon Slayer Mark on his Forehead. This Ability grants the user the power to see the Internal workings of the Human body. By using this ability, the user can see every Bone, muscle, nerve, and even the live Blood flow in the Human Body. There aren't many Users with this ability who appear throughout the story. This ability is very powerful, and Yorichiii was born with it. He always saw the world with this Ability, and he could easily predict his opponent's actions beforehand in a fight.

Early Life, Family, and the Hanafuda Earrings

Yorichii was born in a Samurai family and had a twin Brother named Michikatsu. Yorichii was born with a high fever and the demon slayer mark, and his father believed that this mark was a bad omen and decided to kill him, but his Mother, "Akino," saved him and convinced his father not to kill him on the condition that they would send Yorichii to a monastery when he became ten years old. Akino was the only person Yorichii was allowed to be with, and she made the Hanafuda earrings that Yorichii wore and gave to Tanjiro's ancestors.

Akino was very sick, and Yorichii was the only person in the house who knew it, and he always stayed near her mother until she died when he was seven years old. Since Yorichii was born, he never showed any emotional outbursts on his face, and he did not utter a single word from his mouth until he was seven years old. Before this, everyone believed that Yorichii was deaf.

His father always hated him and would criticize and scold him whenever he saw him, but his older twin brother pitied him and cared for him a lot as he always comforted him and even gave him a flute so that whenever he was in trouble, Yorichii could call his older brother for help.

Birth of Sun Breathing and Its Forms

Yorichii's father made Michikatsu the sole heir of his family and started teaching him Swordsmanship. When Yorichii was seven years old, he was secretly watching his brother learning swordsmanship and became interested in being a samurai since he was always looking up to his older brother, who wanted to become the strongest Samurai.

After seeing his brother practising, he declared his intent to become a Samurai, and everyone was shocked to see him speak, as everyone believed that he was deaf. His father gave him a sword and told the instructor to fight Yorichii and Yorichii defeated him by hitting him four times with immense speed and strength.

Everyone who witnessed this scene was shocked, especially Michikatsu, who believed that Yorichii was weaker than him. Yorichii described this fighting style as an early version of his future breathing style, but he disliked the act of hurting someone and thus gave up his ambition to become a Samurai.

Tragedy of Uta and Yoriichi’s Resolve

Later on, Akino died, and Yorichii knew that there was no one left who loved him in his house and decided to run away from there. Even Michikatsu didn't stop him as he started being Jealous of Yorichii's abilities. After Yorichii left his home, he didn't know what to do and wished to be dead. He started running towards the Mountains for more than 24 hours without showing any signs of exhaustion, and then he stopped in the mountains after

he saw a girl named Uta standing alone in a rice field. Uta's family had died in a plague, and she was left alone and wanted someone's company to live her life, so Yorichii offered to go with her. Yorichii and Uta started to live in Uta's house, and soon they became Travel companions, and after 10 years of their first meeting, they finally married. Yorichii was finally happy and just wanted a normal life with his wife, who shortly became pregnant after their marriage. One day he decides to hire a midwife for helping his wife during her pregnancy and left to home to search for one but he saw a old man who wanted some help and Yorichii helped him and then returned late to his home. after returning he was left in horror as he saw that his wife and unborn child was mudered by a demon which devasted Yorichii Mentally. Yorichii held his wife's corpse for 10 days without even eating or drinking anything, after which a demon slayer found him and told him to bury his wife and child.

Joining and Corps Training, the Corps and Adapting Breathing Styles

The Demon Slayer explained to Yorichii about demons and the Demon Slayer corpse and advised him to join them to fight Demons. Yorichii then decided to become the strongest and end the terror of demons once and for all.

Yorichii is known as the strongest Demon Slayer throughout the Demon Slayer History because in his entire life he never lost a battle, including the battle with Upper rank 1 Kokushibou and the king of Demon  Muzan. Yorichii was born with a flawless body, which always granted him the abilities a person can get through using TCC (Total Concentration Breathing Constant).

Yorichii had an immeasurable amount of stamina as it was shown that when he was Seven years old he ran for an entire day without even getting a little bit of tired. Yorichii could also survive without food and water for more than 10 days.Yorichii's sword can turn into a bright red blade, which can kill the demon's healing ability.

When Yorichii joined the demon slayer corps, he told the Slayers about Breathing Style and taught them how to do so, but none of the Slayers could perfectly use the Sun Breathing Style Due to this Yorichii had to adapt his Breathing Style into other fundamental breathing (Water,Earth,thunder,etc). After learning the Breathing styles the Demon Slayers started awakening their Demon Slayer Marks.

Yoriichi vs. Muzan: The Decisive Encounter

Shortly after joining the Demon Slayer Corps, Yorichii encountered Muzan, and he instinctively knew that he was the strongest demon and that even a scratch from Muzan would kill Yorichii instantly. Muzan Underrestiamted Yorichii because of his emotionless behavior and thought that he was a weak fool and attempted to kill him, but Yorichii combined all his forms into one single attack, thus creating the 13th form of sun breathing, and attacked Muzan with such speed and power that Muzan was left with his head nearly severed and was unable to heal his wounds.

Yorichii understood that his bright red Nichirin blade can even destroy the healing ability of the demon king and he then shifts his focus on Tamayo, who was with Muzan. Tamayo was sitting on the ground, seeing Muzan in this state, but not with despair or terror, but with Hope in her eyes.

Yorichii then decided to deal with her afterwards and shifted his focus on Muzan again and was about to finish him off but he suddenly heard a sound of clenching molars breaking and then saw Muzan's body explode into 1800 pieces. He instantly destroyed 1500 pieces, but was unable to destroy the rest as they were too small.

Tamayo was left hopeless as she yelled that why Muzan cannot die can came to know that the curse didn't affect her, even though she uttered Muzan's name. Tamayo then tells Yorichii about Muzan and how he is a coward and will never appear in front of Yorichii again. Yorichii then asked tamayo to help humans in defeating Muzan, to which she agrees and Yorichii lets her escape.

Exile from the Corps and Consequences

After the battle, when Yorichii returns to the Demon Slayer Headquarters, he was banished from the Demon Slayer corps for failing to kill Muzan, letting Tamayo escape, and was also blamed for Michikatsu turning into a demon. Yorichii was asked to perform Seppuku, which is a ritual suicide in Samurai culture and means to die with honor. But the newly appointed oyakata sama intervenes and saves Yorichii.

Michikatsu’s Fall: From Moon Breathing to Kokushibo

Muzan was so scared of Yorichii that he immediately went to Michikatsu, who was the user of Moon Breathing and the second Strongest demon slayer of the era. Muzan understood Michikatsu's jealousy and offered him to become a demon so that he could live forever and become stronger than his brother.

Michikatsu's jealousy and fear of death led him to become a demon, changing his name to Kokushibou and helping Muzan kill all the Sun Breathing users. They both thought that Yorichii died at the age of 25 because any slayer who awakened his mark was not able to live after the age of 25.

The Final Reunion: Yoriichi vs. Kokushibo

After 60 years of becoming a demon, he was walking through a wheat field and suddenly encountered Yorichii, whom he believed was dead.

Yorichii, seeing his older brother who he looked up so much turn into demon, was devastated him mentally and he started crying. Michikatsu(now Kokushibou) was shocked and relieved once again after he saw his brother crying, as this was the first time yorichii showed his true emotion to his brother.

Yorichii then took his battle stance, and Kokushibou immediately understood that there was no opening in Yorichii's stance. And Yorichii then warned Kokushibou before attacking him, and then he moved forward, slicing Kokushibou's neck. Kokushibou didn't even have a chance to unsheathe his blade. Kokushibou's anger took over him again as he witnessed that his brother, despite being in his old age, still surpassed him greatly.

Kokushibou then prepared to attack Yorichii, but he knew that even Muzan could not defeat him, and Yorichii would just finish him with the next attack, but he saw Yorichii standing there without moving a single muscle. To his shock, Yorichii died a natural death before finishing him off. This angered Kokushibou even more, realising that he couldn't surpass his brother even in his old age and that he would forever remain an undefeated warrior.

Legacy of the Hinokami Kagura and Kamado lineage

Yorichii once saved a person who is later revealed to be the ancestor of Tanjiro and passed down his Hanafuda earrings as well as breathing style in the form of a dance to Kamado’s family. Tanjiro's ancestors then made a tradition to learn this dance and pass down the earrings to their generations. And this tradition is called Hinokami Kagura or Dance of the Fire God.

This was the story of Yorichii, the strongest Demon Slayer throughout Demon Slayer history, and till now, his legacy is alive and helping Demon Slayers to win battle against demons. 

 The only word senpai has to say is " not only yoriichi is him but also he’s the blueprint for Demon Slayer verse."