|Also known as||Muu-kun (by Sora)|
|Hair Color||Light Grey|
|Affiliation|| Sohma Family|
Kaibara Municipal High School
|Parents|| Yuki Sohma (Father)|
Machi Kuragi (Mother)
|Extended Family|| Unnamed Parental Grandfather|
Unnamed Parental Grandmother
Unnamed Maternal Grandfather
Unnamed Maternal Grandmother
Ayame Sohma (Paternal Uncle)
Mine Kuramae (Paternal Aunt)
Hibika Sohma (Cousin)
Chizuru Sohma (Cousin)
Unnamed Maternal Uncle
Kakeru Manabe (Maternal Uncle)
Komaki Nakao (Maternal Aunt)
Michi Manabe (Cousin)
Kou Manabe (Cousin)
|Manga||Another Chapter 1|
Mutsuki is a young man with a slim and relatively tall build. He is noted by his peers to be very attractive with a prince-like appearance, and is often admired for his looks.
Mutsuki takes after his father's silver hair- and eye color, and his mother's eye shape. Unlike his father, Mutsuki has blue-hued colors in his otherwise light-grey eyes, and long eyelashes. His hairstyle seems to resembles his maternal uncle's. He has slightly spiked, near shoulder-length hair with messy bangs covering most of his forehead.
He wears the standard Kaibara High uniform for males with a yellow sweater on top.
Mutsuki presents himself as a very charismatic, attractive, level-headed, and considerate student council member. He is seen as a prince by people around him, but unlike his father, Mutsuki does not mind this and rather takes advantage of this, but only when it revolves around his friends. For instance, he used his looks to get Sawa Mitoma out of some tricky situations, such as being stopped by the landlady on the way to school, and when she was scolded by the principal for coming late on her first day. Because of this, he is described to be very sly, and is not above using different methods to achieve what he wants. According to Shiki Sohma, Mutsuki reminds him of his father Shigure, though not to the same extent; even Mutsuki himself states he isn't as sly as Shigure.
Above all else, Mutsuki is similar to his uncles, Ayame Sohma and Kakeru Manabe. He is very outgoing, joking, confident, and mischievous with somewhat of a flirty streak. He loves teasing people and getting on their nerves, and he also finds humor in many things by saying baffling things to people with a straight face, never losing his cool during these situations. He is very outspoken and frank, and is never afraid to speak his mind. He is also quite air-headed and carefree, and like both of his parents, he is terrible at keeping tidy, which he proudly admits that he takes after his them. He acknowledges his inability to keep things clean, but nonetheless has no motivation to change his habits.
Despite his overall carefree, humourous, and unreliable personality, Mutsuki is a deeply caring, loving, and considerate person who is always looking out for the people around him. When he first meets Sawa, he offers her kindness and support, a factor which helped her to eventually to break out of her shell. He loves to show affection to the people dear to him, as he has several times expressed how much he loves his parents and is proud to take after them. He also loves his relatives (the Sohmas and his cousins) dearly, and he is honored and happy to be able to be around them.
Mutsuki is the only child born to Machi and Yuki Sohma. Mutsuki grew up in a loving household with warm childhood memories. The memory that sticks out the most is a family tradition where he and his parents would wake up early whenever the snow would pile up, and then make trails of footprints in the snow. Thereafter, they would have breakfast together as a family.
Because Mutsuki's parents are close friends with Kyo Sohma and Tohru Honda, Mutsuki ultimately came to know their son, Hajime Sohma, too. The two would often play together as their parents watched over them. It is also stated that once they entered elementary school, they would have sleepovers at Mutsuki's house. Aside from Hajime, Mutsuki grew up with and became friends with the children of his parent's friends, particularly the Sohma children. Additionally, Mutsuki and his cousin Michi Manabe, were raised as siblings.
When Mutsuki entered his first year of middle school, his father told him about the Sohma family and its former Curse, as well as his own history as the Rat. Although Mutsuki was shocked, he appreciated the fact that his father told him about it. Additionally, every suspicion he had about the Sohma family added up; such as witnessing Ren Sohma about to stab Shiki Sohma before Shiki's mother, Akito Sohma, protected him from the attack. He then added how he was glad that he had Yuki and Machi as his parents and that he's happy he gets to live together with them. When Mutsuki described their home as the place he always wants to come home to, Yuki broke down in tears of happiness.
Over time, it is known that Mutsuki became increasingly worried about Shiki, who had begun withdrawing from annual Sohma celebrations. Mutsuki knew Shiki was acting reclusive due to receiving abuse from the older members of the Sohma family, specifically from Ren's side of the family. At one point, Mutsuki witnessed Shiki finding a note in his school bag which read "your mother is human garbage". This made Mutsuki furious and saddened, and wanting to help Shiki, he used Sawa Mitoma as a "bait" to lure Shiki out of his shell.
At the beginning of the story, Mutsuki saves Sawa Mitoma from the admonishment of Principal Makoto Takei. It is later revealed that Mutsuki is Vice President on the student council (under Hajime). He continues to help Sawa when he can.
- Mutsuki inherited a love for the fictional anime Mogeta from his mother. In childhood, he was seen to have a Mogeta plush and a Mogeta alarm clock, and in his teens, he has a Mogeta keychain.
- Mutsuki is the only one of his relatives that aren't put off by his parental uncle Ayame Sohma, and even calls him the "most terrific of all uncles".
- Mutsuki is apparently an extremely bad cook, so much that Hajime has to beg him to not cook.
- Mutsuki likes to garden and has even revived the garden that his father had in his high school days.