Characters / Shimeji Simulation - Shijima Tsukishima

Shimeji Simulation Character Index
Main Characters (Shijima Tsukishima) | West Yomogi High School | Other Characters | Spoiler Characters

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Due to Shijima's nature of being a Walking Spoiler character, every single tropes about her will be unmarked spoilers. You Have Been Warned.

Shijima "Shimeji" Tsukishima

Voiced by: Naomi Ozora (VOMIC)

First Appearance: Chapter 1

Plenty of things happened when I was in my first year of middle school. Things that made me hate it. Ever since then, I shut myself inside my closet for two years. Two years later, a thought occurred to me that it's about time I leave.

—Shijima

^{Click to see Shijima with three mushrooms on her head.}

The main protagonist of the story. A 15-year-old (later 16-year-old) former social recluse and an orphan along with her sister, Shijima later leaves out of her closet after two years, as she starts her term as a first-year high-school student. She lives with her big sister at the apartment complex (danchis) in the middle of nowhere in West Yomogi.

After hiding herself inside a closet, she is later seen with two mushrooms sprouting on her head. While she starts out as a person with an emotional baggage to begin with, Shijima's life later turns upside down for the good when she befriends Majime.

Over the course of the story, Shijima gets involved in Majime's antics, as well as others including her sister and the members of Hole-Digging Club including Mogawa and Sumida. However, she is later involved into a much bigger mystery surrounding the true nature of her world and why things are as is.

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A-I

• Adaptation Amalgamation: Due to essentially being a Transplant of her two previous incarnations from both the picture book and the one-shot, Shijima's entire character is essentially a Broad Strokes merging between the two, with her past characterisation from the former and her current appearance from the latter.
• Adaptational Backstory Change: A strange case since she's been Transplanted twice, both including her original versions from picture book and the one-shot, leading to several changes in her backstory before subsequently merging into one.
  • Unlike in the picture book where Shimeji-chan had the shimeji mushrooms in her elementary before becoming the subject of her bullies' mockery, Shijima in the current manga got her mushrooms during her two-year reclusion since her first year of middle school.
  • While Mina in the one-shot manga becomes a recluse due to the death of her friend Yocchan, Shijima in this manga becomes a recluse where she hid herself inside a closet after an incident regarding an unknown friend of hers. It is heavily Broad Stroked because her slightly risqué moment with Yocchan was completely omitted, leaving only the part where she becomes a recluse, which was eventually carried over to Shijima's own backstory.
• Aesop Amnesia: While Shijima learns the value of friendship it brings, she reverts back to form when she becomes fearful of being merged as one by Majime. This led her to be isolated, yet again, which is an ironic Call-Back to her time as a recluse before the start of the story.
• Affectionate Nickname: Shimeji-chan by Majime and her sister. Later, she is temporarily called Shimejime by Mogawa, which is a fusion of her nickname and Majime's first name.
• The Ageless: A primary case in Chapter 47 where she's over 1,416 years old when the Time Skip happened, yet she still has the body of a 16-year-old teenage girl.
• All for Nothing: Taken to levels in Chapter 43 when she threatened Majime after dreading of being merged by her into one. The result is her being thrown into a world that is devoid of anything, making her efforts completely nothing.
• All of the Other Reindeer: In the non-canon picture book the child Shijima gets bullied her peers for having a mushroom on her head. Gets a case of Who's Laughing Now? when she finally goes out of her isolation and spreads the spores from her mushroom to others while flying, leading to her same bullies to have mushrooms on their heads.
• The Aloner: Her fate eventually becomes this after she was told by Big Sis to isolate herself forever in order to not become involved with the changes, once everything becomes back to normal. She later becomes alone in her own world as shown in Chapter 47's end panel.
• Aloof Dark-Haired Girl: She has a black hair who is aloof (at first) and quiet in most of her appearances.
• Ambiguously Absent Parent: In contrast to Majime who both have parents, Shijima and her sister don't have parents at all and their fates or anything about them are left ambiguous. Justified since they are revealed to be the creations of the simulation and are not biological human beings.
• And I Must Scream: Being trapped and isolated while with her simply dreaming endlessly about Majime is an Understatement. She's essentially still alive after a millennium has passed and as The Hermit it did no favours for her. She's repeating it every single day within those thousand years, which is a much worse fate than death, and it's clear that she feels a strong pang of loneliness every time she wakes up from her dream. Subverted in Chapter 49 when she finally reunites with Majime.
  Shijima: Every time I wake up from a dream, my chest is pierced with a sharp feeling of loneliness.
• Animal Motif: Fish, which is yet a part of her Shared Family Quirks that she obtained from her sister. Her fish pencil case is named "Yoshika", which was named thanks to Majime's insistence.
• Animorphism: In one instance during Chapter 47's finale where her stay on her isolated world for a very long time led her to be turned into a slug. Subverted in Chapter 48 where she goes back to being a human again after riding the train.
• Anti-Hero: Shijima is an Ice Queen who has a major personality flaw, in particular with her past problems as a recluse, as she is often aloof and brooding that her first encounter with Majime started as this. Eventually, however, she later slowly mellows out and becomes friends with Majime and various members of the Hole-Digging Club.
• Apathetic Student: Shijima is rather uncaring of going to school, as it is one of the reasons for her being a recluse during her first year of junior high. Even in the present she's only visiting school for her reasons including attendance.
• Arc Symbol: The two mushrooms on Shijima's head. It symbolises the cycles of death and eventual resurrection. To an extent, her mushrooms are an indirect, walking arc symbol, namely as various, major events of the manga always involve with both.
  • In Chapter 29 Big Sis threatens to remove the shackles of the simulation (a la death) by allowing humanity the free will to change anything they can imagine (a la resurrection). This granted Shijima the ability to Reality Warp after the latter destroy the illusion of the simulation.
  • The above pattern repeats again in Chapter 40 when the Big Sis clone threatens to also do the same thing Big Sis did by destroying what left of the world's natural order (death), only this time to allow humanity to change themselves in an instant (resurrection).
  • Chapter 45 plays this trope straight where a giant shimeji is seen beside Shijima when the simulation's order collapsed to a point (death) that the only option for her, under Big Sis' suggestion, is to go back in time and undo the damages during the school festival, but by sacrificing her connections to the people she knew (resurrection).
• Artificial Human: In Chapter 45, it is revealed that she and her sister were born next to the grassy fields beside the danchis, as a byproduct of the simulation creating them.
• Aw, Look! They Really Do Love Each Other: While she's mean to Majime on the outside at the very start of the story , despite getting annoyed over Majime's attempts of friendship, there are cases where they often care each other. Much more pronounced after the first part of her Character Development after she befriends Majime in Chapter 10 where she no longer shows coldness towards her.
• Batman Can Breathe in Space: Chapter 18.5 shows Shijima freely walking and breathing on the surface of the Moon in space without the need for protective gear.
• Be Careful What You Wish For: Shijima kicks Majime away after what felt like a sex scene between the two, under the pretext of her slowly disappearing. The result of her "wish" sent her to an empty, barren world without Majime and their home, leaving her alone in the middle of nowhere. Her actions not only ticked off another Wham Episode but also the real Darkest Hour of the manga as a whole.
• Big "NO!":
  • In Chapter 1, Majime asks Shijima if she wants to be her friend. Shijima responds with a succinct "no" in a deadpanned manner.
    Majime: Be my friend.
    Shijima: No.
  • Also on the receiving end from Majime in Chapter 8.
    Shijima: I'm trash, though.
    Majime: You're not!
• Big Word Shout: Played for Laughs in Chapter 1 where she slaps Majime's hand when she attempts to touch her hand, ending with a "DON'T TOUCH ME!" as her reaction.
• Broad Strokes: Due to being a Transplant character that appeared in some of the author's previous works, Shijima's characterisation is a case of Adaptation Amalgamation, which fuses between her characterisation from the picture book and the one-shot. However, certain aspects from both incarnations were significantly altered and combined altogether to the current Shijima.
  • In the picture book, Shimeji-chan got the mushroom during her elementary years and became the target of bullying by her peers, causing her to be a recluse. In the canon proper, it was significantly altered where she instead got her shimeji in her first year of middle school during her two-year isolation inside her closet.
  • In the one-shot Mina (another inspiration for Shijima) is friends with Yocchan whom she was romantically in love with and had a sex scene at one point, before her untimely death led her to become a social recluse. The sex scene and her relationship to Yocchan was completely omitted, leaving only the recluse part transplanted onto the current Shijima's backstory.
• Butt-Monkey: As shown in the non-canon picture book, she gets poked fun of by her classmates due to having a shimeji mushroom on her head, even calling her names like "Mushroom Girl", leading her to be a recluse.
• Byronic Hero: At first. She has a painful past that led to her reclusive life and is extremely jaded and pessimistic to others where her very first reaction to Majime's attempt of befriending her is to give her the cold shoulder. It's shown in the first nine chapters where she refuses to befriend Majime, despite the latter's persistent attempts to do so. She softens up later when she accepted her friendship in Chapter 10.
• Call-Back: One of Shijima's shimeji mushrooms grow larger during Chapter 22 when it was snowing after Majime wished for it. It grows yet again in Chapter 45 when it was also snowing, only this time it was done due to the complete collapse of the simulation.
• Character Development:
  • Shijima starts off as a somewhat jaded Ice Queen, largely in part to her tragic past as a Hikikomori, preferring to be alone rather than befriending with someone. Initially the case since Shijima's female friend committed suicide during her first year in middle school, which was the focal point of her reclusion. From the first ten chapters of the manga her friendship with Majime is more so reminiscent between ice and fire (with Shijima being the "ice" and Majime being the "fire"), with their polar opposite personalities often come in conflict with each other. After the events of Chapter 10, Shijima finally defrosts her old personality, later becoming the first true friend to Majime.
  • Zigzagged much later, when Shijima goes into a reverse character development from the start of Chapter 43 when she became increasingly fearful of being merged by Majime, causing her to go back to her old, reclusive past again.
• The Comically Serious: Her deadpan snarking and her aloof personality is often the source of laughs, especially towards the optimistic Majime.
• Contrasting Sequel Main Character: To Chito of Girls' Last Tour.
  • Chito is a post-apocalyptic survivor along with her friend Yuuri from a technologically advanced Crapsack World within the future and is the main driver of the Kettenkrad. Shijima is an ordinary teenage girl in a seemingly idyllic town of West Yomogi, who became reclusive for two years due to a certain tragedy regarding her friend in the past.
  • Both also deal with existential crisis, but while Chito deals with the slowly negative outcomes of her and Yuuri's journey in the empty, snowy world, Shijima deals with struggles in her life after her reclusion and how it affects her school life before befriending Majime.
  • Chito is only friends with Yuuri, while temporarily to people they encounter like Nuko, Kanazawa and Ishii. Shijima initially struggled to make friends due to her pessimistic worldview attributing to her past and befriended Majime after Chapter 10, as well as befriending the others including Majime's mother and the members of the Hole-Digging Club.
  • While Chito is a Bookworm and a Wrench Wench who has knowledge of machinery and especially the Ketenkrad, Shijima shows little interest in studies and has no skills in machinery, but makes it up when she gets Reality Warping powers.
  • Both are orphans of their own circumstances since birth. Chito was an orphan born in a town under a civil war and was taken care of by an old man, later named as "Caretaker". Shijima was an orphan along with her sister after they were revealed to be created by the simulation next to the grass within the danchi.
  • Similarly, they're also alive by their prolonged existence. Unlike Chito who is dead and has been a living soul for a thousand years without ageing, Shijima is chronologically a thousand years old and is still alive without any change to her physical appearance.
  • Whereas Chito is a flesh-and-blood human, Shijima is an Artificial Human who is a byproduct of the simulation's creation.
• Damsel in Distress: In Chapter 10 where she was pursued by a giant crab in the Dream World, before her foot got stabbed by a glass shard, causing the animal to finally catch up to her and attempts to devour her.
• Darkest Hour: Twice.
  • Chapter 30: A Downplayed example. When she realises that Big Sis has been causing problems across the simulation, she becomes disillusioned with her true nature, causing herself to distance and apologise to the Gardener about her actions.
  • Chapter 43: Played straight. After becoming angry over Majime and the almost merging between both of them, Shijima is thrusted into a world of nothing but a black void with no existence of Majime at all. From there it's a long, agonising journey for her, where she encounters Yomikawa before breaking down in tears over her actions. She encounters Big Sis, as a fish, where she was told to separate herself from others once everything goes back to normal in order to not become involved with the changes, causing her to become The Hermit again in Chapter 47 where she settles in her own world, wishing to be reunited with Majime again.
• Dark and Troubled Past: Shares this with Big Sis, as she and her sister are considered to be unwanted around West Yomogi in the past, largely due to them being orphaned. Another part of the trope plays out, when her two-year reclusion started during her first-year of junior high, due to a suicide attempt that costed the life of her female friend.
• Dark Is Good: She has black hair, but she is clearly not evil. Though she's often aloof and quiet, as well as unsociable.
• Deadpan Snarker: Her being prone to apathy sometimes leads to throwing sarcastic lines mostly towards Majime and she has quite done this a lot.
  • When Majime's efforts to befriend Ayaka and her friends badly failed, Shijima questions her with this.
    Shijima: (reading a book) What were you even doing? Could it be that you also want to make friends?
  • Also happened during their introduction moment in Chapter 2.
    Shijima: "Shijima" also means "Silence."
    Majime: I'm Majime Yamashita. You can call me Majime.
    Shijima: You sure don't personify it well, Majime-san. ^note Majime means serious and diligent, but it is an Ironic Name as she exhibits neither of those traits the name's definition is.
    Majime: Whaa-? Sure I do-! I'm totally diligent!
    Shijima: Only your glasses look the part.
  • In Chapter 3 where Majime falls down into a hole that Mogawa created, where she simply ignored her. Instead of helping her out, Shijima simply snarks at her by asking about going home instead. It wasn't until Majime goes into Covert Pervert mode when she states how she can see Shijima's panties.
    Majime: Oh, I might be able to see your panties from here.
    Shijima: I'm going home.
    Majime: That was a joke! Don't go!
  • Chapter 17 takes this in spades when she looks at Majime dressing up in various swimsuits at the mall's fitting room, with one snarky comment after the other.
    Majime: Well?
    Shijima: The frills look like seaweed.
    Majime: There!
    Shijima: That looks so adult-like it's bothering me.
    Majime: ...
    Shijima: Looks like underwear.
    Majime: !!!!
    Shijima: Drop the pose.
• Defrosting Ice Queen: A part of her Character Arc. In the first few chapters of the manga, Shijima often refuses any form of friendship from Majime, due to her Dark and Troubled Past, claiming that it is considered a hassle to begin with. Chapter 10 is where Shijima finally gets over it, as she accepts Majime's friendship.
• Despair Event Horizon: Chapter 43 takes this to an extent after she casted Majime out, leading her to realise in Chapter 44 how much she became too careless about her own actions.
  Shijima: I am sorry, I got too excited to finally be able to talk to someone. But I was too careless. Until next time... If we have the opportunity to meet again in the future, let's do it.
• Determinator: Despite staying in solitude for a very long time at the final chapters of the manga, which borders to Time Abyss, Shijima constantly clings to see Majime again. Her wish gets fulfilled when she rides a strange train while visiting many, many planets before landing to Majime's world as her final stop.
• Divergent Character Evolution: Before the manga existed, Shijima is basically a transplant of her two previous incarnations who both each have different personalities of their own. The current Shijima in this manga is much more divergent than the previous versions of her, who has developed an entirely different character that is a mix of her previous versions with various changes to it, as well as a much more fleshed-out backstory, different personality and appearance that is absent from both.
• Dragged into Drag: A same sex variant. A flashback scene shown near the end of Chapter 14 shows Shijima and her unnamed female friend during their elementary years, with the former being dressed-up as a doll, complete with a girly dress and a ribbon on her head. While she is seen as cute, that does little to reassure her.
• The Drifter: At the start of Chapter 48 Shijima leaves her own world and travels to countless planets with a train, whilst also stopping a few of them in her final quest to find her after a millennia has passed.
• Epiphany Therapy: Done this by herself in Chapter 10. She commented to Majime how she doesn't like being alone and through the horrifying experiences she went through in the Dream World, she finally realises that she doesn't want to be forever alone.
• Fatal Flaw:
  • She prefers to be by herself and doesn't bother interacting to others, to the point that the said flaw bites up her ass during her travel to the Dream World in Chapter 10 by herself when she got injured in the process and the crab caught up on her. Gets over this flaw when she befriends Majime after she was saved by her, commenting that she doesn't like to be alone.
  • Shijima is extremely codependent towards Majime, who serves as a Living Emotional Crutch to her, and it shows throughout the story she only makes four friends within the Hole-Digging Club. Though in a matter of Irony, Chapter 43 shows how she gets increasingly fearful in meeting people that is not Majime, which becomes even more obvious when she's scared of losing her identity in fear of being merged into one by her. And she instead opted to kick her one and only emotional crutch, leading her to cause problems in both herself and the world around her.
• Fate Worse than Death: Being forced to separate away from the people she knows for a millennia as well as her waiting for Majime that did not happen led her to deal with an increasing pang of loneliness for a very long time. All in her house within her own world that is surrounded by a black, empty void.
• Festering Fungus: She has two mushrooms (temporarily three in Chapter 6) just growing out of her head, seemingly due to her living inside a closet for that long. In Chapter 45 one of her Shimeji mushrooms grew larger.
• Flashback-Montage Realization: After Shijima travels into the recreation of the origins of life created by the Long-Limbed Woman, she later goes into a realisation that she still once knew the people she met 1400 years ago, including Mogawa, Yomikawa, the Gardener and the rest of West Yomogi, who were destined to become their own best selves.
  Shijima: I remembered the people I met before. Everyone was trying to push themselves to be their own best selves. Sometimes it would greatly expand... Or be narrowed by someone else... But they kept living their lives no matter the struggle.
• The Fog of Ages: Being in seclusion for one thousand years causes her to forget her old, yet abnormal life as a normal teenage girl in West Yomogi. Ironically, she still remembers West Yomogi when she told the world God, the Long-Limbed Woman, about it. Subverted when she remembers the people she once met after entering inside the Long-Limbed Woman's creation.
• Foil:
  • To Majime in many ways, as part of their main dynamic as the story's character duo. Both are teenagers and are best friends to one another. While Majime is The Anti-Nihilist whose goal is to be friends with each other and is a happy-trigger optimist, Shijima is a nihilistic Aloof Dark-Haired Girl and a loner who dislikes befriending others, preferring to be a recluse due to her past. Even furthering the contrast, Majime lives with a very stable family including her (sometimes absent) father and mother with quirky traits of their own right. Shijima, on the other hand, only has a big sister who is more interested in her own experiments than taking care of her, despite being a case of the Promoted to Parent as they don't have parents at all.
  • She also has a main contrast to her sister, despite essentially being a Mirror Character to her. While Big Sis often stays at her own home who is focused more on her experiments than taking care of her, Shijima is a Loner-Turned-Friend who actively goes out with Majime and are close towards each other; where she has established some friendships within her circle, including the Hole-Digging Club, the Gardener and Yomikawa. Big Sis is The Smart Girl who is extremely intelligent, being on the forefront of creating her technologies for her goals and is essentially a fast learner; while Shijima, who is a fast learner like her sister, is a Lazy Bum who is a complete pessimist, not bothered to do anything that is considered productive.
• Forgotten First Meeting: Her best friend with Majime is not the first time. In fact in Chapter 14, as shown in a flashback scene, her real first friend was an unnamed classmate of hers in her elementary years when she visited her own home when she was forced to be dressed up as a girl.
• Freak Out: Her main reaction when she realises that she's eventually going to be merged with Majime, leading to her kicking her best friend out of desperation.
• Gone Horribly Right: Her attempts to stop the eventual merging with Majime becomes this when she encounters a desolate world formed from her wish to prevent it from happening.
• Grade Skipper: Zigzagged. Shijima skipped the last two years of her junior high and started her first-year of high school. However, she never spent the last two years of junior high, as she was at least 15 to 16 by the time she started high school, so it was implied that she was mostly home-schooled by her sister for two years.
• Hair-Contrast Duo: She has black hair as she is quiet and level-minded, in contrast to the blond-haired Majime who is loud and ditzy.
• Hates Being Alone: All the talk about her reclusive life, Shijima clings to be friends with others and she becomes Majime's first friend in Chapter 10, despite all the reservations at first. Though she becomes alone again in Chapter 43 onwards when Majime disappeared thanks to her actions and her goal is to find her, even arriving at Majime's world after passing by at many planets!
• Hates Being Touched: Shijima does not appreciate it, when people are touching the two mushrooms on her head.
• Have We Met?: During Shijima's trip to the train, the passengers who looked suspiciously similar to her former neighbours asked when they met her before. Shijima casually says that they're her neighbours from the complex, before the duo answered that they don't even know her, let alone they barely heard of her. What Shijima doesn't realise is that she's talking to the souls of Chito and Yuuri from Girls' Last Tour and not her former neighbours.
• The Hermit: Spent her last two years of junior high hiding in her own closet. Played Straight again in Chapter 47 when she is revealed to be the only person in her own world.
• Heroic BSoD: Chapter 44 reduces Shijima into a sobbing mess when she contemplates how she was finally able to talk to someone (Majime), despite the very fact that she forcibly told her to leave at the previous chapter.
• Heterosexual Life-Partners: After Chapter 10, Shijima is very close to Majime as her Only Friend.
• Hikikomori:
  • Was one during her middle school years, after her female friend committed suicide. She later literally comes out of that trope, two years later, at the beginning of the story. Played With in Chapter 17 where she comments how her going to the mall or even visiting another neighbouring town are first-time experiences for her after being a shut-in for two years.
  • Happens again in Chapter 47 when it is revealed that she's all by herself in her own world who is a recluse again.
• Hypocritical Humor: She sarcastically asks this question about having friends to Majime when the latter gets told off by Ayaka to stop butting onto someone's conversation. And ironically enough, the said question is being asked by Shijima, a social recluse herself.
  Shijima: (to Majime) Could it be that you also want to make friends?
• I Just Want to Be Normal: Not only she has lived her life as a recluse for two years, but she also had to slowly witness her sister's rather ambiguously maligned plans, which includes her dismantling West Yomogi's foundation, a plan that she never knew but the readers do (through Foreshadowing) until it was revealed in Chapter 30. Temporarily Lampshaded in Chapter 34, when it is implied that she wants nothing of her sister anymore, due to the incident in West Yomogi. However, in Chapter 37, she shows little to no antagonism towards her.
  Shijima: I'm really sorry for the weird changes that my sister made...
  • Subverted when her life becomes abnormal again in Chapter 40 after the Big Sis clone has caused another reality-altering moment to the point that natural order is a thing in the past. And she's later saddled with the task to reverse it, five chapters later, to Big Sis' wishes, after the fabric of her world collapses to a breaking point.
• Ice Queen: Before her Character Development, Shijima is shown to be unfriendly and cold towards Majime, often attempting to refuse any of her efforts to accept her friendship. They have been friends, in a sense, but not in permanent, friendly terms. That is largely due to a trauma of her friend committing suicide that led Shijima to being a recluse, thereby she refused any attempts of friendship at first. That is until Chapter 10, where she subverts this trope after befriending Majime as a true friend.
• In the Blood: She's technically the spitting image of her sister, who has the same blue eyes and black hair and are both aloof and quiet.
• Irony:
  • Her mushrooms grew during her two years of being a recluse inside her closet, and she's still alive. This is due to mushrooms often being a symbol of a living being's decay and eventual decomposition and yet Shijima is alive and well.
  • A part of her Sarcasm Mode when she asks about Majime wanting to be friends with others. It's for the fact that Shijima is a friendless social outcast.
  • Her friendship towards Majime is a major case of this. Shijima clings to be friends with others, before her wish becomes true when Majime finally defrosts her Ice Queen persona and befriends her, to the point that she becomes her one and only Living Emotional Crutch over the course of the story. Yet she does the exact opposite when she instead threatens her to stop being merged by her in Chapter 43, causing her to become a recluse again after being separated by her, leading her to revert back to her old personality.
• It Began with a Twist of Fate:
  • When Shijima partakes her sister's dream-walking experiments in Chapters 8 to 9, it creates the real Establishing Character Moment where the manga is more to it than just simply being a surreal slice of life.
  • Her friendship with Yomikawa in Chapter 19 indirectly starts the major plot point of unveiling the true nature of her world when she and Majime becomes more involved with it, especially in later chapters.
  • A more significant case is when she forcibly tells Majime to leave out of fear of being merged, resulting in the world before her to be empty. This started the final end of the manga.
• I Will Find You: Her final goal is to reunite with Majime once again as shown in Chapter 48 where she rides a train before departing to Majime's world at the final panel. By the end of Chapter 49, her goal of reuniting with her is finally realised.

K-Y

• The Kirk: To Majime's McCoy and her sister's Spock. Despite her nature as an Ice Queen (at first) aloof girl, Shijima is the more composed member of the trio, being the middleman for Majime's idealistic optimism and Big Sis' logical intellectuality.
• Lazy Bum: Despite in one case in Chapter 8 where Shijima manages to beat Majime's test scores, Shijima's a very pessimistic girl who isn't bothered to do anything productive, particularly including school. Lampshaded by this very quote about her in Chapter 3:
  "Was a shut-in for two years before high school, during which two stalks of shimeji mushrooms grew on her head. Can't be bothered to do anything and is a pessimist."
• Leave Me Alone!:
  • Her interactions with Majime for the first time started out as this in the very first chapter, who simply wants to ignore her as she reads a book and refused many of her attempts to befriend her.
  • Invoked in Chapter 43, where after a rather risqué scene with Majime, she forcibly kicks Majime away from her, fearing that she would slowly disappear. She gets her own wish... At the expense of now being sent to a deserted, chaotic part of the world they were in where Majime is nowhere to be seen and with their house gone from sight.
• Limited Wardrobe: Her three usual signature outfits. She often wears her school uniform, her signature white knee-length jacket and her pajamas as her staple outfit over the course of the story. Even after 1400 years later.
• Living Emotional Crutch: Deconstructed. She's very emotionally dependent on her best friend Majime to the point that she's the very reason for the start of her Character Development after becoming friends with her. It's the fact that she is her true friend and is unwilling to be separated from her life. But it's a deconstructed type of a crutch since it made Shijima much more very dependent to her, almost to the point that she's increasingly more unwilling to befriend others outside of her social circle (including Majime and the members of Hole-Digging Club). It gets From Bad to Worse in Chapter 43 when Shijima actively dreads to be merged with Majime, all to the point of telling her to stop, causing Shijima to go into a Heroic BSoD in the next chapter about her recklessness.
• Locked Out of the Loop: Subverted. While Shijima is (at first) unaware of the simulation's true nature, she and Majime are slowly identifying many anomalies that have been happening at random across West Yomogi, even though readers are slowly aware of what Big Sis is up to in regards to uncovering the true nature of her world. This doesn't even count the numerous reveals about the world being a reality simulation and her true existence as a creation by the simulation, of whom which were only known to her, Majime and especially Yomikawa.
• Loner-Turned-Friend: She became a recluse from society due to an unknown incident in her middle school years and refused to be friends with others. Over time, she is not only close friends with Majime, but also to others like Mogawa, Sumida, Yomikawa and even the world God she encounters in Chapter 48.
• Meaningful Name: Shimeji, as it is the name of the mushrooms that grow around her head. It mostly goes into Affectionate Nickname territory where she is called by her nickname Shimeji-chan.
• Merger of Souls: Almost in one scene during Chapter 43 where she was having a suspiciously romantic interaction with Majime, before it suddenly goes completely nightmarish when she goes into a Freak Out moment over being closely merged by her. She doesn't take it well and resorts to threatening her to stop it.
• Minor Living Alone: In a sense by the time the third Wham Episode of the manga kicks in, she is all by herself who is living on her own and she's only a 16-year-old teenager barely reaching her adult years. Emphasised much further in Chapter 47 when she is the only person living in her own world. Somewhat Zigzagged as she's, by the time the story's 1400-year-Time Skip occurred, 1416 years old, though she is still a teenager in appearance.
• Mirror Character:
  • To her sister. Both are very similar in appearance, are black-haired girls with quiet and aloof personalities and both befriended a blond-haired girl who is the exact opposite to them in terms of personality, with Shijima to Majime and with Big Sis to Yomikawa.
  • To Sumida, as they're both quiet high school students and are Shrinking Violets who are shy and unsociable towards others, except for their own social circle.
• New Superpower: She attained Telepathy from her third shimeji mushroom, which allowed her to read anyone's thoughts. Though it was temporary. But she later gains Reality Warping abilities, right after Big Sis altered West Yomogi.
• Nice Job Breaking It, Hero: Of the things Shijima can do, kicking Majime out under an understandable fear of being fused into one eventually started the true Darkest Hour of the manga. Unlike the two previous world-altering events that Big Sis and the clone did, both of which are permanent to begin with, her actions are much more permanent that she ends up becoming The Hermit in Chapter 47.
• No Social Skills: At the start. She spent her two years as a social outcast, which in return made it hard for her to be friends with others as she comes off as distant and icy. She rarely converses to complete strangers and instead opts to talk to the people she readily knew firsthand, including Majime in particular. Slowly goes out of it, however.
• Only Friend: Played With. Her only friend and the closest one is Majime and even in some cases her next-door neighbours from the former danchis. Her friendship with the rest of the Hole-Digging Club members is a case of it being transactional as she has temporary attachment, let alone little attachment, to them. Gets a case of Deconstruction when she becomes really dependent to Majime as her own Living Emotional Crutch that she's slowly unwilling to become friends with others. And said chance was blown away when she becomes all alone by herself after the disastrous get-up with Majime.
• O.O.C. Is Serious Business: The normally calm and stoic Shijima is later reduced to tears in Chapter 44, after realising the weight of her own actions she caused towards Majime.
• Out of Focus: Temporarily in Chapter 46 where Majime is the principal focus of the chapter. In fact her appearance in that said chapter is merely reduced to her being a statue sitting next to the Majime statue.
• Pals with Jesus: She easily befriends the Long-Limbed Woman in Chapter 48, who is actually a world God who has known the true nature of the world before West Yomogi and the town itself, which would be considered unheard of for 1400 years. In fact she's the only one of the two people to still remember the town's existence along with Shijima, despite the thousand-year-Time Abyss that passed by.
• Pay Evil unto Evil: Downplayed and Played for Laughs. In the picture book, after being subjected to being a Butt-Monkey by her classmates for her shimeji mushrooms, Shijima goes into a Who's Laughing Now? moment where she spreads the spores from her now-gigantic mushroom, causing small mushrooms to sprout from the heads of her bullies. Yet her classmates don't even notice it.
  "Sparkling as they fall, what the spores deliver equally to each of them: A tiny present."
• Really 700 Years Old: Comes in play after Chapter 46 as it went into a massive time skip 1400 years to The Future. Not only she's been alone in her own world with no outside contact, but she's also still alive for millennia if counting how the people in simulation cannot die at all and is at least 1,416 years old with her body remaining the same as her old self a millennia back.
• Sarcasm Mode: When she asks Majime about her wanting to make friends in a very sarcastic manner, it quickly caused Majime to offer Shijima to be her friend. And Shijima flat out refuses the moment she asks that offer.
• Screw This, I'm Outta Here:
  • Played for Laughs in Chapter 3 when Shijima mockingly leaves Majime, who is in Mogawa's hole that she dug, after Majime poked fun of seeing her panties.
  • From Chapters 30 to 34, where she sees Big Sis' true nature and her involvement in the alteration of West Yomogi, wanting nothing of her. She went on apologising to the Gardener regarding Sis' actions. Though Chapter 37 subverts this trope when she no longer shows bitterness towards her.
• Self-Made Orphan: Subverted, as she and her sister had no parents at all. They're both Artificial Humans who were both created by the simulation along with others within the simulation.
• Shared Family Quirks: She shares her sister's main quirk of being quiet and aloof, as well as their Animal Motif being fish.
• Shrinking Violet: Due to her being inside her closet for the past two years, Shijima is initially shown to be really shy, preferring to avoid friendships, as exemplified when she attempted to shot down Majime's attempts of doing so.
• Straight Man and Wise Guy: She is the Straight Man to Majime's Plucky Comic Relief, often being the Voice of Reason to the latter's comical antics.
• Stop Worshipping Me: When Shijima enters the Chiho Tribe Kingdom for the first time, many of its people worship her when their promise was fulfilled. Shijima, on the other hand, has none of it.
• Strong Family Resemblance: Bears a very identical resemblance to her sister, who both has her black hair and blue eyes. She also shares her sister's Tareme Eyes. Averted, as she's not born from a parent, but she and her sister were created by the simulation.
• Super-Deformed:
  • In one panel in Chapter 2, Shijima turns into a slug while she is staring at her own pencil case that was being held by Majime.
  • Chapter 3 has two instances occurring when both of them were joining for a school club. The first chapter shows Shijima literally going wide with her head the length of a crab, with Majime telling her to "not be so wide about it". The second is when she turns into a formless human with just her eyes and mouth.
• Tareme Eyes: Her eyes look droopy all the time, which fits her nature as a Shrinking Violet. Though she's also an aloof girl (at first) who is mostly bored.
• Telepathy: Temporarily in Chapter 6, where her third shimeji mushroom seemingly gave her the ability to read minds, as seen when she was able to read Majime's thoughts easily.
• Time Abyss: She has spent as a hermit in her own world for over a thousand years, whom she barely even remembers her own past life except for Majime, where she still has memories of her despite the long-distance physical separation between both of them.
• Tomato Surprise: Shijima's past is completely unknown where the only thing that was even mentioned about it was her time as a recluse, at first... Until the big reveal shows that Shijima knows her true origins as a creation of the simulation all along, a fact that she withheld to the audience for the past 45 chapters. Since the entire world is simply a simulated reality and not real, it makes sense.
• Tragic Dropout: Happened twice.
  • Shijima dropped out during her middle school term, when she was in her first year of her junior high, largely due to a tragic past regarding her female friend's attempted suicide and eventual death, leading to her reclusion inside her own closet for two years. Subverted when she goes out of her Hikikomori phase at the beginning of the story.
  • Because of the incident with Sis and the Gardener after Chapter 30, Shijima, along with Majime, are no longer in school. Subverted in Chapter 37, when they are seen going back to school again.
• Transplant: Shijima, both in design and personality, existed a bit before Shimeji Simulation in a series of web illustrations. The two prominent examples of this trope includes:
  • Shijima, as just Shimeji-chan, appears in a picture book detailing her life being ostracised by her elementary school classmates for having two shimeji mushrooms on her head. Ironically, the ostracism part was retconned, where the current backstory of Shijima having two mushrooms was significantly altered. Instead she got it during her two-year reclusion in her middle school years and the bullying part was completely omitted.
  • She appears in a slightly risque oneshot as Mina, where part of her depression is caused by a female friend, Yocchan, who she has sex with committing suicide. The backstory and Mina's character design was carried over to the current Shijima albeit with some Broad Strokes, such as the omission of the risque moment as well as her backstory with Yocchan.
• Used to Be a Sweet Kid: Three of the shots of Shijima's memories as seen in her dream during Chapter 9, where she was seen smiling brightly during her childhood. Certain events that happened in her life, including her reclusion, however, have changed her dramatically into the stoic she is in the present.
• Walking the Earth: Or rather Riding The Train Beyond Earth. Shijima's goal during Chapter 48, the manga's Dénouement Episode, is to ride a mysterious train that travels to many planets just to find Majime, while also encountering the souls of Chito and Yuuri. Eventually that said goal happens later at the end where she reaches Majime's world.
• Walking Spoiler: She's the protagonist of the story, but talking about her gives away immediate spoilers. Even mentioning the very quote she speaks in the first chapter during her looking at the mirror gives away a heavy Foreshadowing about her true nature as an Artificial Human. Talking about her Tomato Surprise moment also spoils the main reveal that Shijima and Big Sis are not Self Made Orphans.
• When She Smiles: Shijima rarely smiles over the course of the manga due to her personality and her past. So it comes as no surprise when she smiles in Chapter 2, despite it being considered a one-off moment. However, it is still a heartwarming feeling.
• Who's Laughing Now?: At the end of the picture book, the non-canon manga to Shimeji Simulation, Shijima is seen flying above the sky with a giant mushroom, whom she uses it to scatter the spores from it to her bullies at the end, leading to them having mushrooms within their heads.
• Who Wants to Live Forever?: By the time 1400 years have passed, Shijima's fate is infinitely worse than death when she becomes immortal, unable to die at all but to think of Majime, sleeping every single day with each passing dream, while her loneliness in her own world continues to sharpen further where she forgets everything about her past. And she does it every single day.
• Vitriolic Best Buds: Due to being virtually the contrast to Majime, both of them tend to sometimes do not go along, with Shijima often keeping Majime's antics in line. Despite that, they are very close to each other.
• You Can't Go Home Again: In spades. As part of her attempt to not interfere with the changes, according to Big Sis, not only she's not allowed to go back to her home world, but she's forced to be in solitude in her own world forever.

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