|“||I study on my own and I've learned that the world radically changes its makeup every few years or decades. Even if I follow my parents' instructions, that may not be how things work by the time I grow up. That's why I'm working on my own so I won't get panicked when things go that way. Just in case it turns out my parents were wrong in the future, I won't have to blame them.||”|
Somei is a pale, bespectacled young woman with short brown hair styled in a choppy bowlcut, alongside slate grey eyes. She wears gloves to hide the scars sustained in the First Large-Scale Invasion. Before she joined Border, she had shoulder-length hair. In her trion body she wears the standard Operator uniform, a pair of gloves, an earpiece, and pink-framed glasses.
Somei is quietly confident and impassive in all situations. Even as a young girl she did not betray emotion when her father forbade her from seeing her best friend, or following the collapse of her house. Neither did she falter when rescueing her best friend from the rubble instead of her own family, which she framed as a decision dictated entirely by logic as Katori's roof 'was easier to lift'. Early in her life she developed the conviction that the world changes radically every few years and that studying would help her navigate the new times, a belief which allowed her to find her own source of motivation to meet the academic expectations her parents had of her. After the invasion she resolved to climb up Border's ranking. Even while being bluntly crude when she deems it useful, she does not intervene in her teammates' arguments unless they detract from the task at hand, despite the deterioration of morale; nor does she demand Katori make a stronger effort, presumably due to to the certainty that she will not change just because others insist.
Somei is Katori's childhood friend and next-door neighbor. She would often come to Katori's house, she studying and Katori playing videogames. When Somei was prohibited from visiting Katori, Katori swapped bedrooms with her brother, which faced Somei's, requesting a window to be cut out so that they could chat. Katori tried to play it cool by pretending that she just wanted to rearrange her room, to no avail. After learning that Somei saved her instead of her own family, in addition to her plans to enlist in Border, Katori decided to join with her, convinced that with her talent they would be able to achieve anything. Despite Somei studying much harder than Katori when they were younger, she was not bothered by her friend boasting about achieving superior grades with little effort, although she did warn her that she intends on climbing to the top of Border. On occasion Somei does chide Katori for not taking her duty seriously enough, but unlike Wakamura she never seems to prod her to improve, presumably because she knows that at the end of the day Katori will do what she wants. To this day she remains unfazed by her temper tantrums, her frankness occasionally frustrating her. However, she encouraged her when she feared that she would not be able to evolve, sensing that Katori was finally willing to make an effort. Somei is one of the few people who can make an emotionally charged Katori listen to reason, whether it be while fighting or when she bickers with Wakamura. However, she does not intervene in the arguments unless they directly affect the performance of the team. Katori and Somei are on a first-name basis, neither using honorifics.
Miura and Somei are cousins, and it is through her that Miura joined Katori Unit. She lived at his house for a while after losing her own. When his attempts to pacify his teammates are unsuccessful, he relies on Somei to step in, although her interventions are focused on getting Katori and Wakamura to behave professionally rather than reducing the attrition between them. Miura and Somei call each other by their first name, without appending an honorific.
Wakamura is attracted to Somei due to her calm and collected demeanor, and especially likes watching her study. Like Katori, he respects her enough to end his skirmishes with his captain when she chides them, with her appearing to take on the role of conciliator on occasion, although it is not uncommon for her to let the arguments fizzle out on their own. Like his teammates, Wakamura trusts her enough to follow her directions blindly in combat. Somei and Wakamura call each other by their first names, she appending the honorific -kun, he using -san.
Somei's father used to require that his daughter excel in her studies, and forbade her from seeing Katori after she failed to rank first in her cram-school tests. Somei obeyed, although she resumed talking to her friend when she had a window installed right in front of her own. Somei used to try to study for her own sake as much as possible, believing that her parents' instructions might be obsolete by the time she grows up, and that if she motives herself to learn on her own, she will not have to resent them. When her family and Katori were buried during the First Large-Scale Invasion, Somei chose to dig out Katori instead of her parents, claiming that she made that decision because the roof of Katori's house seemed lighter.
It can be presumed that, like her husband, Somei's mother wanted her daughter to excel at academics in order to secure a bright future. She appeared to be against her husband's affirmation to prevent their daughter from seeing Katori, although it does not seem as though she actively opposed it.
Somei has a secret crush on Arashiyama.
Somei and Katori's brother have known each other since childhood. Since he called her by her first name with the diminutive suffix -chan and greeted her with a smile, evem later trading rooms with his sister so that the girls would be able to speak to one another, the two are probably on amicable terms.
Since she often went to Katori's house when they were younger, Somei knew her parents well and was well-liked by them. Katori's mother was fond of praising Somei for her dedication to her studies vis-à-vis her own daughter's lack of effort. She also became concerned when she had the impression that Katori was rude to her friend, although the latter never took offense, or attempted to get her to chime in to reduce Katori's ego. Somei would on occasion befuddle Katori's mother with her astounding intellect. Katori's mother addresses her by her first name followed by the honorific -chan.
Since she often went to Katori's house when they were younger, Somei knew her parents well and was well-liked by them. Katori's father addresses Somei by her first name followed by the suffix -chan, acting cheerful around her. His public displays of affection toward his daughter used to give Somei pause.
- (To her teammates) "All three of you... We are supposed to be working. So take it seriously."
- (To Yōko Katori) "Yōko... I'm sorry. My analysis wasn't good enough."
- (To Katori's mother) "It's hard to change someone who doesn't wish for change. Not looking for change means they are, to an extent, satisfied with what they have already. You could say that is desirable, in a way."
- (To Katori) "I study on my own and I've learned that the world radically changes its makeup every few years or decades. Even if I follow my parents' instructions, that may not be how things work by the time I grow up. That's why I'm working on my own so I won't get panicked when things go that way. Just in case it turns out my parents were wrong in the future, I won't have to blame them."
- (To Katori) "Don't worry. It'll be all right."
- (To Katori) "I only chose who was more likely to survive. Don't worry about it."
- (To Katori) "If that's what you want to do, then go ahead and quit. You should do what you want, Yōko. That is the type of person you are."
- (To Katori) "If you can feel the sting of defeat, then there's still room for you to become stronger."
- Somei likes working through problems, hot chocolate, and friends. She also enjoys her life at Border.
- According to the author, prior to her past being revealed, there were rumors among fans surrounding Somei's gloves which ranged from her being a germaphobe, to having prosthetic hands, to being a poison-using assassin.
- In the English version of Volume 16 her birthday is incorrectly transcribed as being on July 1st.