We are currently nine episodes deep into season 3 of Demon Slayer, and Mist Hashira Muichiro Tokito's backstory has finally been revealed. Each Hashira has their own unique history, and Muichiro's is one that is extremely heartbreaking. The tragic events of Muichiro's younger childhood, which actually happened fairly recently, resulted in him becoming a very changed boy.
This might be stating the obvious, for any tragedy will change a person forever, but Muichiro underwent a complete metamorphosis. For he once was a more innocent and optimistic kid, who ultimately became the polar opposite. In fact, he resembles a familiar figure in his life now, his late twin brother Yuuichiro.
The Tokito Twins Become Orphaned
Muichiro was born into a family that chopped wood. He, his brother and their father all chopped wood together. One stormy day, Muichiro and Yuuichiro lost both of their parents. Their mother died of what initially was a cold but developed into bronchitis, and their father died falling off a cliff when he braved the storm to get medicinal herbs to treat his wife. This left the brothers to fend for themselves at only ten years old.
Yuuichiro and Muichiro were totally different personalities, which made daily life difficult. Yuuichiro criticised his family heavily after his parents died, calling their compassion useless and actions stupid. Where Muichiro believed in their father's karmic philosophy of good deeds returning to you, Yuuichiro found this hard to believe, since the result of this deed killed him. In his eyes, their father would be alive if he stayed home instead of venturing through the storm to save a woman who was beyond saving. Where Muichiro felt that Yuuichiro was too harsh and mean, Yuuichiro was just being incredibly blunt and honest. Yuuichiro called Muichiro useless, saying that the "Mu" in his name is the equivalent of the "in" in "ineffective" and "invalid".
About a year later, Master Ubuyashiki's wife Amane came to visit the brothers. She told them that they are descendants of fine swordsmen and have the ability to use Sun Breath. While Muichiro was enthusiastic and optimistic about becoming a swordsmen to help people, Yuuichiro thought it was a crock of nonsense. Yuuichiro chased Amane away every time she visited, even pouring water on her at a point.
According to Yuuichiro, how can "someone can't even cook rice" become a swordsman. He scolded Muichiro for spouting optimistic nonsense like that, which is exactly how their parents acted. He claimed that if their mother did not continue working without telling them she was sick, she would not have gotten worse. Additionally, he said that if their father listened to him and his mother to stay home, he would not have gone on an optimistic mission to procure medicine. He believed that they were not special, for only the chosen few were granted by the universe to pursue noble quests like that. To him, all they can do is just live day-to-day and "die like dogs". Muichiro let his brother go on his rant, each sentence hitting like a punch to the gut.
Muichiro Changes
After this intense fight, the boys did not speak for a long time. Summer arrived, a really hot one at that. They were visited by a demon one night, and Muichiro was about to lose his last family member. The demon lunged at Muichiro, only for Yuuichiro to jump in front of him in defense. The demon ended up cutting off his arm and causing excess bleeding. The demon taunted them, calling them worthless woodcutters and saying that the world would keep on if they died. As Muichiro cradled his dying brother, he looked the demon in his red eyes and felt an intense emotion that he never felt before: rage. He does not even remember what happened, only coming to and realising that he had impaled, hit, kicked and bashed the demon through the night till he crumbled to dust in the sunrise.
Heavily weakened, he crawled back inside his home to Yuuichiro. He found his brother alive, but barely. Yuuichiro was praying to gods, pleading them to spare Muichiro, the brother who's kind and wants to be useful. Yuuichiro felt that he only got on Muichiro's way of wanting to be a good person, and so if anyone should be punished it should be him. As Muichiro held his brother's hand for the last time, Yuuichiro's dying words were that the "Mu" in Muichiro represented the "in" in "infinity", and that if he did anything to help others then he will be able to unlock infinite strength.
Amane found them and tried to save Yuuichiro, but it was too late. She and her children healed Muichiro, but his memories were now lost. He trained incredibly hard, even while he was healing. His raw talent and steely discipline resulted in his Hashira status after merely two months, making him the youngest Hashira. Muichiro became a much more hardened person. Gone are his days of innocent optimism, for now he became a much more cold and distant individual.
In the present, Muichiro's younger doe eyes are gone. He speaks to Tanjiro in the same blunt and pessimistic manner that Yuuichiro used to speak to him with. Tanjiro's familiar philosophy of good deeds returning sparks something in Muichiro, but he responds with Yuuichiro's familiar answer: it does not mean anything. All this is too familiar to him. Even Muichiro admits, he became his brother.
Yuuichiro Tokito
Yuuichiro was the complete antithesis to Muichiro. Where Muichiro believed in positive philosophies and possessed a certain kind of naive optimism, Yuuichiro believed only the pessimistic. He never saw the good in anything, even in grief he chastised the way his parents died. To him, life dealt its worst hand at them, so how dare they believe that anything positive can come their way. Even the demon that killed him reaffirmed the way he views himself.
It transpires that there was a reason for his cold behaviour. Muichiro was a softer person, so Yuuichiro perhaps felt that he needed to be harder for their survival. To him, the gods still curse those as virtuous and pure like him, so if they won't protect him then he must. In death, he remorsed the fact that he was so mean to his little brother, and lamented that being nice in such an unforgiving world is something a select few are born with.
It seems that Muichiro, Insect Hashira Shinobu Kocho and Kanao Tsuyuri are given the same treatment by the author of Demon Slayer, keeping siblings alive throught their behaviour. Just like Shinobu and Kanae, Muichiro is a living reminder of previous family. Being twins, they look identical. On top of this, they wear two versions of the same outfit. Yuuichiro's clothes had black mist patterns, now Muichiro dons an all-black outfit. More starkly, like Shinobu and Kanae, Yuuichiro is kept alive by Muichiro's behaviour. His old personality has been replaced with his brother's colder one.
Demon Slayer is available to stream on Netflix & Crunchyroll.