Muichiro is a short, young man of light complexion with long, straight hair of a black color that faded to pale turquoise as it approached his waist. He wore his hair loose with two clumps protruding slightly from each side of his head, a set of marginally shorter hair left down to frame his face, and unruly bangs over his forehead. He also possessed large, empty-looking, mint-green eyes. His eyes and hair were traits shared with his twin brother, Yuichiro Tokito.
Muichiro wore a dark, slightly turquoise-tinted version of the Demon Slayer uniform. His uniform had longer, looser sleeves that were more reminiscent of those of a kimono than of the standard cuffed uniform. Along with this, the lack of bands of cloth wrapped around his calves gave his uniform an overall loose and sizeable appearance.
Muichiro is an air-headed individual who seemed to constantly wander off in thought and never focus on one thing. Impassive and, at times, obtuse, he tended to think only for himself and operated on logic alone, never letting emotion guide him. However, he had been shown to get serious when it is required and is devoted to his position as the Demon Slayer Corps' Mist Pillar.
However, before the death of his twin brother when he is 11, Muichiro's personality is that of a much more caring individual. Having originally taken after his father, he is shown to display a high level of kindness and understanding than his demeanor as a Demon Slayer, believing that he should aim to do good for others if he wanted good to be done for him. However, after his brother is killed at the hands of a demon and Muichiro subsequently lost his memories, he held an omnipresent rage deeply suppressed inside of him that inevitably drove his later training.
After his memories returned, he started expressing more emotions and became more confident in himself. He also learned other expressions such as displaying sarcasm and smugness towards Upper Moon Five, Gyokko.
Muichiro and his older twin brother, Yuichiro, were born to a woodcutter and his wife. When they were 10, their mother caught a cold which developed into bronchitis and killed her. Their father, who had gone to fetch medicinal herbs for their mother during a storm, ended up falling off a cliff to his death.
The two orphaned siblings survived together, with Muichiro taking after the emotional and kind nature of their father. Yuichiro instead held a cold and impassive outlook on life.
In the following spring, Oyakata's wife, Amane Ubuyashiki, arrived to recruit the twins for the Demon Slayer Corps. Muichiro's excitement is opposed by Yuichiro's unwelcoming and rejecting reception. In an outburst, Yuichiro revealed that he blamed the death of their parents on their hardworking and selfless nature and adopted a cold outlook, hoping to keep himself and his brother alive.
While Amane continued to visit the twins, Yuichiro chased her away each time. In the following summer, a Demon arrived at their cabin during the night and attacked, resulting Yuichiro losing his left arm while trying to protect Muichiro. As the Demon badgered them for their worthlessness, Muichiro lost himself in a rage and destroyed the Demon with all the tools at their disposal and wooden logs.
By sunrise, the Demon withered into ash and Muichiro dragged himself back to the house. There, he found Yuichiro near death praying to the heavens that his brother might survive. He laid there grasping his brother's hand as he passed away. Amane and her daughters later arrived to heal Muichiro.
Afterwards, Muichiro would lose his memories and leave his old life behind to serve the Demon Slayer Corps, and, due to his strength, he quickly rose to the rank of a Pillar. With his memories gone, he began taking after Yuichiro's personality. He also met Kyojuro Rengoku during this period in the Demon Slayer Corps, who told him they should do the best they could as fellow Pillars.
After Tanjiro Kamado is brought to the Pillars' meeting for interrogation, Muichiro is present and later introduced as the Mist Pillar. When questioned on how he felt about Nezuko Kamado being kept alive, he retorted that he did not mind and would forget about the circumstance anyways.
When Tanjiro suddenly interrupts Kagaya in the middle of his meeting with the Pillars, Muichiro flicks him in the head with a pebble and advises him to not interrupt their master, telling him to leave.
Muichiro is seen receiving the news from his Kasugaigarasu about Kyojuro's death.
While Tengen Uzui is battling against Gyutaro, Gyutaro compliments him on his supposed natural talent for fighting. Tengen denies this and instead thinks of Muichiro and Gyomei Himejima as individuals with exceptional aptitude towards swordsmanship.
Muichiro first appears in the Swordsmith Village when he is seen arguing with Kotetsu. He tries to convince the latter to provide him with the key to Yoriichi Zeroshiki, slapping him when he refuses to comply. Tanjiro intervenes, grasping his arm and attempting to crush it like he did to Genya Shinazugawa after the Final Selection. However, to his surprise, Muichiro does not budge despite having a smaller frame and thinner arms, instead punching Tanjiro in the stomach and reprimanding him for his weakness. He sees the box on his back and reaches for it, sensing a demon, but Tanjiro slaps his hand and tells him not to touch it while rescuing Kotetsu from his grasp. Kotetsu continues to refuse handing over the key even under torture, and Muichiro chides him for his talk, stating how he is isting a Pillar's time and that swordsmiths are only good for making weapons. Tanjiro interrupts, angry at Muichiro's inconsiderate attitude, but he gets knocked out by him.
After Tanjiro regains consciousness, he goes with Kotetsu to watch Muichiro fight against the mechanical doll, witnessing him breaking it. Muichiro remarks about the useful training and takes one of Zeroshiki's swords, asking Tanjiro to dispose of his broken one. Tanjiro doesn't sense any malice coming from him, but he is still upset about his attitude.
Later that week, Muichiro pinches Tanjiro to wake him up, inquiring him about the whereabouts of Kozo Kanamori, his new swordsmith. When Tanjiro offers to go with Muichiro to find him, the latter questions why he would do so. Tanjiro replies that helping others could end up positively affecting himself, leading to Muichiro suddenly feel a sense of familiarity and he questions Tanjiro about what he just said. However, before he can do so, Nezuko awakens and breaks the flow of their conversation, Muichiro wondering where he saw her before. Their conversation is suddenly interrupted by the entrance of Upper Moon Four, Hantengu.
Muichiro immediately attacks Hantengu using Breath of Mist, Fourth Form: Advection Slash. Hantengu dodges and he comments on his speed, attacking him again after Tanjiro and cutting off his head. Tanjiro, remembering the situation with Daki and Gyutaro, yells at Muichiro to keep focusing as Hantengu splits into two bodies, Sekido and Karaku. Karaku attacks Muichiro and blasts him out of the building and into the forest.
As he rushes to return to the village, Muichiro sees Kotetsu being attacked by a demon. He contemplates saving him but suddenly remembers Tanjiro's words and beheads the demon, telling Kotetsu to escape. When Kotetsu intensely thanks him and apologizes for his original hatred towards him, Muichiro's memories spur as he remembers recovering under the care of the Ubuyashiki family.
Kotetsu leads Muichiro to where Kozo is. As Kozo starts making for the shed to retrieve the new blade, Muichiro pulls him back as he senses the presence of Upper Moon Five, Gyokko. Muichiro attacks him, but Gyokko moves to different pots and avoids his slashes. He summons more fish demons that send an array of needles towards Kozo and Kotetsu, but Muichiro shields them and tells them to move out of the way. Gyokko reveals the needles are poisonous and berates Muichiro, resulting in another sudden memory recurring to him. He tries to attack Gyokko, but gets trapped in his Blood Demon Art, Water Basin of Hell, his attempt to break out using Breath of Mist, First Form: Hanging Sky, Distant Mist unsuccessful. As he thinks about his approaching demise, he suddenly hears his father's speaking from Tanjiro's body. Kotetsu swiftly arrives to provide him with a breath of air and he is able to break out using Breath of Mist, Second Form: Eight Layered Mist, remembering it is his father who said the same thing as Tanjiro had earlier.
After escaping from the water prison, Muichiro's memories of his past all come back. The anger over his brother's death manifests into his Demon Slayer Mark, his speed and abilities dramatically increasing as he goes into the shed and attacks Gyokko, who comments on his relaxed face. Gyokko retaliates with his Blood Demon Art, Octopus Pot of Hell, and Muichiro's blade breaks trying to cut it, prompting Kozo to quickly hand him his new one. Muichiro slices through the demon's attack and thanks Kozo, in which he replies that he only followed the instructions of the late Tetsuido. At the mention of his name, Muichiro remembers his old swordsmith's worry for him and internally apologizes, remarking that he is okay now and uses Breath of Mist, Fifth Form: Sea of Clouds and Haze, landing a blow on Gyokko's neck.
Muichiro and Gyokko start insulting each other, with the latter growing furious after the former insults his pot. He uses another Blood Demon Art, Ten Thousand Gliding Clay-fish, but Muichiro easily counters it with Breath of Mist, Sixth Form: Moonlit Mist and Breath of Mist, Third Form: Demisting Blast, slicing the head of the demon's molt as he escapes to a tree. When Gyokko tries to show off his new form, Muichiro's indifferent attitude towards it enrages him again and he attacks, which Muichiro dodges and smiles, commenting on the uselessness of his offense.
Another scuffle between the two ensues, with Gyokko using his Blood Demon Art, Deadly Scales of War and Muichiro responding with the form he personally developed: Breath of Mist, Seventh Form: Obscuring Clouds. When Gyokko tries to find him in a sea of mist, Muichiro effortlessly decapitates him.
In the aftermath of the battle, Muichiro starts foaming at the mouth due to poison and falls unconscious after verifying Kotetsu is alive, his family congratulating him on a job well done in his consciousness.
After the battle ends, Tanjiro and Muichiro thank each other, Muichiro for the sword and Tanjiro for helping him regain his memories. Mitsuri Kanroji later pulls them all into a group hug.
Abilities and Powers
As a Pillar of the Demon Slayer Corps, Muichiro is a very powerful swordsman. He is incredibly talented despite his young age as he is able to become a pillar just two months after starting his demon slayer training. After awakening his Demon Slayer Mark he is able to defeat Upper Moon Five with relative ease even after the Upper Moon assumed its true form. His techniques were even praised by Upper Moon One for being well developed for one so young. Despite this, Muichiro is still severely outmatched in his encounter with him, having his arm cut off after the Upper Moon One drew his blade for the first time. However, later on in the fight, he proved instrumental in Upper Moon One's defeat. After unlocking the See-Through World and the ability to dye his Nichirin Blade in a crimson red color as well as willingness to sacrifice his own life, he is able to land a critical blow on Upper Moon One.
- Master Swordsman: Being a Pillar of the Demon Slayer Corps, Muichiro is one of the most powerful and skilled swordsmen in the entire organization. Muichiro's sword techniques even impressed Upper Moon One.
- Enhanced strength: Despite his build appearing to be the smallest and seemingly weakest of the Demon Slayers and Pillars, Muichiro has been shown to be stronger than Tanjiro Kamado by a wide margin. He is able to knock him out with a neck chop. He didn't budge at all when Tanjiro held on and gripped his arm with all of his strength, despite Tanjiro being strong enough to break Genya Shinazugawa's arm even before he began training as a Demon Slayer.
- Omnipresent Rage: Muichiro attributes the origin of his willpower towards training and strength towards the awakened rage within him.
- See-Through World: Similar to Tanjiro, Muichiro obtained the ability to see the "see through world", which granted him superhuman kinetic vision similar to Kanao Tsuyuri. The ability enabled him to see the muscles, blood flow, and joint movement of his opponents, which allowed him to accurately predict and anticipate the movements and attacks of his opponents.
- Crimson Red Nichirin Blade: During his battle against Upper Moon One, Muichiro gained the ability to dye his Nichirin Blade in a crimson red color, giving it the ability to hamper the enhanced regeneration of Demons.
- Demon Slayer Mark: Muichiro's mark is first awakened during his battle against Upper Moon Five, Gyokko. The mark appears as several red mist-like designs that cover the entirety of his body, most noticeably on his face and arms. While the mark is active, his offensive and defensive abilities are increased by several times their usual strength, the power increase being enough to grant him the strength to not only operate a severely poisoned body but effortlessly kill an Upper Moon as well. However, once the mark vanishes, he immediately begins suffering from the effects of the poison, showing that the mark is only effective for as long as it is manifested.
Breath of Mist Style (
- First Form: Hanging Sky, Distant Mist (
壱ノ 型 垂 天 遠 霞Ichi no kata: Suiten Tōgasumi?): A straightforward thrust attack.
- Second Form: Eight Layered Mist (
弐ノ 型 八 重 霞Ni no kata: Yaekasumi?): Muichiro unleashes multiple slashes one on top of each other in quick succession.
- Third Form: Demisting Blast (
参ノ 型 霞 散の 飛 沫San no kata: Kasan no Shibuki?): A circular slash that blows away projectile attacks from enemies.
- Fourth Form: Advection Slash (
肆ノ 型 移 流 斬り Shi no kata: Iryūkiri?): A quick slash from the sheathe reminiscent of an Iaidō technique.
- Fifth Form: Sea of Clouds and Haze (
伍ノ 型 霞 雲の 海Go no kata: Kaun no Umi?): Muichiro charges towards an enemy attack at high speed and unleashes a flurry of slashes.
- Six Form: Moonlit Mist (
陸ノ 型 月の 霞 消Roku no kata: Tsuki no Kashō?): Muichiro leaps high in the air and sends a series of countless ranged slashes downwards.
- Seventh Form: Obscuring Clouds (
漆ノ 型 朧Sachi no kata: Oboro?): A technique created by Muichiro himself. It a technique used to disorient the enemy by drastically changing the tempo of ones movement. When he shows himself, his speed will appear to be extremely slow but when he hides, he moves in the blink of an eye.
- The first kanji of Muichiro's first name, "nothingness" (無 mu?), is noted to also be used to write the word "infinity" (無限 mugen?).
- According to Tengen Uzui, Muichiro is one of the two people who became a Pillar only two months after becoming a Demon Slayer, the other being Gyomei Himejima.
- Muichiro wears loose and oversized clothes in order to disorient enemies, as they would not be able to see his limbs and joints moving so well. This is supposed is hinder their ability to predict Muichiro's movements.
- Muichiro can't have pets because his crow would get jealous.