Muichiro is a boy of fair skin complexion and short stature. He possesses a lean-muscular build that is described to be thinner and smaller than Tanjiro's, but deceptively strong.[4] He has straight waist-length hair, transitioning from raven-black to turquoise. He wears 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 has large empty-looking turquoise irises with a teal center, making his overall appearence identical to his older twin brother Yuichiro. Muichiro is an air-headed individual who seems to constantly wander off in thought and is unable to focus on anything. Extremely impassive, and at times obtuse, he tends to think only for himself and operates on logic alone, never letting emotions guide him. This makes him seem apathetic and indifferent. However, Tanjiro Kamado sensed that Muichiro wasn't being apathetic on purpose as he didn't emanate any animosity. Despite his mostly uncaring and unserious demeanor, he has been shown to become serious when it is required and is intensely devoted to his position as the Demon Slayer Corps' Mist Hashira. Additionally, he seems to display a cold and arrogant side, as shown when he violently shakes down Kotetsu, calling him stupid, claiming that his time as a Hashira was important, more so than his own, and that all that the swordsmiths could do was make weapons.[6] Despite this, Muichiro doesn't seem to be indifferent towards Kagaya Ubuyashiki, most likely due to his immense respect for his master. Muichiro's original cheery and optimistic disposition. However, before the death of his twin brother when the siblings were eleven, Muichiro's personality was that of a much more compassionate and optimistic individual, the polar opposite of his current disposition. Having originally taken after his father, he was shown to display a higher level of kindness and understanding, believing he should aim to do good for others if he wanted good to be done for him. When told by Amane Ubuyashiki that they were descendants to Demon Slayers who used the first Breathing Style, Muichiro became excited at the prospect of being able to protect people, but Yuichiro scolds him for his optimism and believes they couldn't do anything, despite being descendants of Demon Slayers from the past.[7][5] After his brother was attacked by a demon who insulted them for being meaningless, Muichiro becomes consumed by pure rage and attacks the demon. Muichiro then witnesses his brother's final moment and death, ultimately leading him to subsequently lose his memories and hold a perpetual rage deeply suppressed inside of him that inevitably drove his future, intense training. After this memory loss, he started exhibiting the indifferent attitude of his twin brother he is known for as a Hashira, becoming hostile, aloof, and unbothered by the opinions of others. Following his battle with Gyokko and reuniting with Tanjiro after the latter's battle with Hantengu, he warmly thanked Tanjiro for helping him regain his identity and showed his concern for Tanjiro's wellbeing. Muichiro's mood changes upon seeing Tanjiro Muichiro's compassion for Tanjiro. During his later interactions with Tanjiro, Muichiro begins to regain his memories of his past, causing him to behave more maturely and seriously, even choosing to help Kotetsu when his life was in danger instead of ignoring him. After regaining his memories, Muichiro began expressing more emotions and became more confident in himself, even starting to care more for his peers in the Demon Slayer Corps. He also starts exhibiting emotions common for someone his age, particularly childishness and immaturity when interacting with other Demon Slayers. Additionally, Muichiro appears to be evidently biased towards Tanjiro after his battle with Gyokko in the Swordsmith Village, as his cheerful demeanor when around him was replaced by a cold indifference when around other Demon Slayers, as seen when instead of letting his trainees pass his training like with Tanjiro, Muichiro firmly instructed them to proceed with their training, and showed clear annoyance over their incompetence. [8]. However, he is shown to be more aware of himself and those around him, evident when he realized that Obanai Iguro had a crush on Mitsuri Kanroji, which surprised Gyomei Himejima. His kindness also aids him in building friendships among the Demon Slayers and creating happy memories like the ones back when he lived with his family. Despite his young age in comparison to his Hashira brethren, Muichiro is an incredibly talented and skilled member of the Demon Slayer Corps, who was noted by the Flame Hashira Kyojuro Rengoku to be more skilled than he was at his age. Even before becoming a Demon Slayer, he was able to completely overpower a demon using only wooden stakes and farming tools. He’s 14 years old and is dating Guest.