Having multiple personalities can be a lot stranger then one might initially believe.
Boku wa Mari no Naha is a strange manga–definitely the strangest I’ve read in a long while. But that doesn’t make it bad at all, of course not. On the contrary, it’s one of the most fascinating stories I’ve experienced as of late. You can read more on why exactly I think so in my review of the story, but for now, I’d like to focus on one particularly interesting part of it: its depiction of Dissociative Identity Disorder.
Before I get any farther into analyzing one very, very broken mind, I’d like to give a heads up–there’s HUGE spoilers ahead for Boku wa Mari no Naka. Huge, in that you will not be able to experience this story in remotely the same way, if you read this analysis before the actual manga. So I HIGHLY recommend you take a look at it beforehand, I promise it’s a pretty good read.
That being said. Let’s get started.
A Trip Into Mari’s Mind
So. Throughout the course of the manga, it is rather unclear just what Mari is like, as we’re being told the story from Isao Komori’s point of view. Trapped in Mari’s body, the young man Isao Komori is understandably confused, as to who Mari is, and goes through quite a journey to figure out who this girl really is. And by the end of the series, it’s clear that Mari is a BROKEN individual. Messed up in so, so many ways.
Here’s a last warning; huge, and I mean gigantic, huge, spoilerific spoilers ahead. It’s okay if you stop now.
Alright.
At the end of the series, it’s revealed that “Isao Komori,” is actually one of two alternate personalities that Mari constructed for herself. The pathetic, horn-dog, disgusting loser she envisioned as Isao Komori is actually another guy entirely–one who lived a life that Mari wanted for herself.
Coming from a home that placed huge amounts of stress on her, Mari wanted nothing more than to be free of her own life. To be someone else–to escape her household, with a mother who was domineering over her, and a father who was always gone. And one day, she saw someone who was living a life that, to one, might look pitiful and disgusting, but to her, was the greatest thing in the world.
She saw a recluse, a guy who came home everyday, jacked off, lived off adult magazines, and was otherwise…pathetic. A guy who didn’t do ANYTHING worthwhile with his life, seemingly without a care in the world. A guy who was living a life free of people telling him what to do–worrying only about his own circumstance. To Mari, this was perfection, a life that she wanted, and so, she became obsessed with this guy. To the point where she spied on him, broke into his house, read his journal–and eventually, suddenly, convinced herself, that she had become him.
This is where the story begins, with Mari believing she was Isao, a guy thrust from his old life, into the body of some other girl. For all he knew, this girl was a stranger, one he had no idea how to treat. All he could do was wonder, who was he? Who was…she?
Now, this might seem weird at first. How could Mari forget herself? But considering the influences of her second alternate personality, it makes just a bit more sense.
As a young girl, “Mari,” was actually another girl, another person entirely. This young girl’s name, was Fumiko–a name given to her by her doting grandmother. However, with her grandmother’s death, Fumiko’s mother was able to mold the young girl into whoever she wanted to be, name and all. Fumiko became lost beneath the mask of the person now named “Mari,” to wander her adolescent subconscious.
In the story, once “Isao” learns about Fumiko, he passes out, and becomes a catatonic wreck, unable to move, unable to feed himself. It is only through the intervention of his–Mari’s–friend, that he is able to bring himself back to a functioning state. Even then, Isao remains the one in control, knowing about Fumiko, but not being controlled by her. She existed as a small, separate personality, a repressed part of Mari that remained unacknowledged for a long, long time.
The ending of Boku wa Mari no Naka then, has Mari coming to terms with the existence of her two alternate personalities, accepting them as parts of herself. She is able to come back to her body, saying goodbye to her two alternate personalities, while acknowledging that they will be with her forever. Going on, Mari is able to seemingly live a normal life, moving on from this strange experience with Isao and Fumiko, a stronger person.
Now, that’s all very interesting. A potentially inspiring story, one with a lot of information to digest…but now, what exactly does this story hint at in real life terms?
Diagnosing Mari With DID
As one might expect, what Mari/Isao/Fumiko struggle with throughout the story is what many people colloquially know as Multiple Personality Disorder–or, psychologically speaking, Dissociative Identity Disorder. With, in this case, three different personalities that carry their own independent perceptions of the world and people around them, Mari certainly seems to qualify as someone with DID.
The official Diagnostic and Statistical Manual of Mental Disorders, or DSM, has narrowed down identifying DID to these five criteria:
- Two or more distinct personality states.
- Amnesia must occur–not remembering personal information, traumatic events, and everyday events.
- The person must be distressed by the disorder, having trouble functioning in one or more major life areas.
- The disturbance is not part of normal cultural/religious practices.
- The symptoms are not due to substance abuse.
Throughout the manga, it becomes clear that Mari has DID, qualifying for every single one of these major criteria, while also showing several miscellaneous signs of the disorder.

Each personality is “well-ingrained, with its own memories, behavioral patterns and social relationships that govern its behavior,” as seen by how ‘Isao’ and Mari were two completely different entities, that behaved differently, to the point where it was clearly noticeable.
Mari had amnesia, unable to remember anything before her ‘Isao’ personality took over, and almost certainly had problems trusting others. Hostility and anger began to grow, as ‘Isao’ became more and more frustrated with the situation he found himself in. And of course, there were extensive problems with sexual adjustment, as it was shown that ‘Isao’ struggled with repressed sexual desire. Masturbating, kissing people of both genders, and of course, feeling guilt about his desires, the manga makes clear that sexual adjustment is a huge problem, especially considering Isao’s perception of himself as male.

That begs the question though–with Mari being ‘Isao,’ a male alternate personality in a female body, how exactly do these split identities work? Why do they exist, and why do some manifest like Isao, while others appear to be repressed, like Fumiko?
Well, this is where an interesting concept must be understood–the idea of having an alternate personality, or an “alter.”
An Introduction to “Alters”
“Alter” is not a purely psychological term, but is very commonly used in regards to the alternate personalities of DID. Alters are basically the multiple identities that live within the same person, that, in effect, “share” the same body.
And indeed, these alters are VERY different. From age, to gender, to name, to even memories and appearance, they tend to differ drastically. Psychologically speaking, they often are COMPLETELY different from their original personality, to the point of having physical differences as well. With “different vision, medication responses, allergies…heart rate, blood pressure readings,” and more, these personalities are far more than just constructs of the head.
These alters can vary drastically from person to person, and typically appear to serve specific purposes for different people. Some are given names, while others exist only with titles, but they all tend to emerge in people with histories of abuse or other sources of overwhelming stress during childhood. Alters are then created, in order to deal with stresses that just can’t be handled by the child.
And, interestingly enough, there are a LOT of different kinds of alters that have been recorded. Infantile alters, psychotic alters, “twin” alters, and even animal alters are recorded, all linked to general trauma. Oftentimes used to cope with stressful situations in some respect, they can often hold the memories that are too traumatic for the main person to bear, or even take on an entirely new personality, used to cope with the stresses of daily life.
Now, in regards to Mari’s alters, we are presented with two different types: Fumiko is a child alter, created to hold the memories of her life before her Mother’s abuse, while Isao is what would be called an “introject,” or “copy alter.” Fumiko, not showing up throughout most of the story, has a rather clear purpose, being created to deal with the trauma Mari has endured as a child.
Her child-like, yet mature ideas, as well as her memories of traumatic incidents in Mari’s life, very clearly reflect real life child alters. However, what seems a lot more interesting to me, is how Isao was created: as a projection of what Mari believed the real Isao to be.

Introjection, generally speaking, is a term used to indicate taking in the thoughts and ideas of other people as your own. It’s a process that happens naturally as we grow up, and normally, this results in kids, adolescents, picking up the habits of those around them, whether they be friends, idols, or parents.
Now in Mari’s case, and in the case of those with DID, this introjection takes a different form: a personality, that is what they imagine someone else to be. From celebrities, to fictional characters, to yes, even people of the opposite sex, these “copy alters” tend to be formed by religious/ritual abuse, or, as in Mari’s case, general trauma. Wishing, more than anything else, for an escape from the world her mother dictated for her, Mari escaped into the reality she constructed for herself: the world of the lazy bum, Isao Komori.
So, we now have a more clear idea of who exactly Mari’s alters are, why they existed, and of course, their real-world parallels. However, in regards to Mari’s catatonic, unresponsive state, we have to look more towards how exactly these alters formed. Specifically, we must acknowledge the trauma that caused this all to happen.
Trauma in Regards to DID
Mari’s past is a troubled one, filled with stress from all sorts of factors–factors that, for the most part, we don’t get to see for ourselves. However, we are given enough information to see just what sort of past Mari might have had, to see why exactly she developed DID in the first place.
As I have mentioned, alters tend to exist in order to deal with traumatic events in childhood. This can take many forms, and as WebMD puts it, the trauma usually consists of “extreme, repetitive physical, sexual, or emotional abuse.” This abuse is almost always long-term, and can even be caused by a frightening home environment, potentially leading even to PTSD at the same time.
Basically, it all starts in childhood–and wouldn’t you know it, Mari’s childhood wasn’t exactly sunshine and roses.
As a child, Mari’s birth name, Fumiko, was chosen for by her grandmother, to the chagrin of Mari’s actual mother. Upon her grandmother’s death, Fumiko found her name forcibly changed to a much “cuter” name, Mari, at a young age, presumably around 4 to 7, by the looks of it. All things considered, it’s safe to say that Mari wasn’t exactly a fan of this change.
The way in which we view Mari’s perception of the world is vaguely terrifying, and leads one to imagine just what was going through her head during the years leading up to the story. Based on what we see, Mari appears to view the world from a skewed lens, even casual situations turning into detestable moments, all because of this name she didn’t want to accept: Mari.
Her perception of even the daily situations in life, appear to be something out of a nightmare. Mari’s mother is portrayed as a wide-eyed, distorted, scary creature, associated with this fake name. Meanwhile, she appears to look at her brother and father, and see no affection that can make it up–with an absent father, and a neutral brother, Mari’s perception of her family is…rather sad, to be honest.
What’s more important here, however, is her perception of herself. Depicted with an empty, blanked out face, Mari appears to be living a fake existence–as someone who is not herself, as someone who is an outline, of what her Mom tells her to be. As such, upon seeing Isao Komori, someone who does what he wants, no matter how lazy, or detestable he may be, it is clear exactly why Mari may have escaped, wanting to live as Isao Komori, more than nothing else.
And, well, we know where that led.

Being forced to have a name she hated, along with being forced to endure generally abusive parenting with no escape in sight, could certainly provide a level of trauma for a child. In fact, the means in which this trauma occurred, might very well have further increased the chances of DID occurring Mari in particular.
For people who have DID, their alters are born simply because they needed another personality to cope with the trauma they endure. Where a guy who was sexually abused may create a female alter, or a physically abused child may have an alter that copies their abuser, these situations…tend not to directly target a person’s identity. Rather, the person is simply placed in a stressful situation, and do what they must to survive.
However, for Mari, the source of her trauma, was a disregarding of her very identity. As a character mentions in the series, Mari was like a doll for her mother, lacking her own free will, and not being affirmed or loved as a child to make up for it. And, if Fumiko was only 6-7 years old, based on Erikson’s theory of Psychosocial development, mistreatment would here would only lead to inferiority, and problems forming an identity in adolescence.
Essentially, Mari’s past was filled with emotional abuse from her mother, who neglected to affirm her identity, and instead, forced her to create another identity, that she couldn’t help but hate. This abuse led to the creation of Fumiko, who harbored these memories, as well as the creation of Isao, who let Mari escape her dire situation.
But then the question remains, finally–how exactly does it all work out? How does this fractured personality recover? For this, we can look to the story’s ending.
Learning to Accept The Past, Alters and All
The ending of Boku wa Mari no Naka is a touching one, yet might feel vaguely stereotypical to the uninformed. After all, words like “always being with you” and “we’re always here inside,” are so easily abused, in regards to the dead. However, in regards to the story’s depiction of Dissociative Identity Disorder, this wording is, in my opinion, fantastic, and perfectly accurate.
Alters in real life are, contrary to what one might think, not completely disruptive mental aberrations. They are how an individual may deal with excessive stress, the companions that kept them company when they had none, and ultimately, are truly a part of them. In fact, the goal of therapy is not normally to get rid of alters straight away–rather, it is about reconciling these alters, integrating them into one personality, and, most importantly, confronting the trauma that created them.
People with DID testify to this, that usually, alters don’t disappear straight away. Rather, in the process of recovery, they integrate into the core personality, sometimes in a single moment, but usually over a span of time. Sometimes, people even choose to not integrate their personalities, choosing instead to work with them, side-by-side, to do life together.
It’s a strange concept to consider. But it is one that the ending of Boku wa Mari no Naka encapsulates perfectly.
Having realized the existence of Fumiko, Isao decided, once and for all, to figure out who exactly he is. By finally having access to what he believed was actually “his” journal, he is able to spark some memories, and realize exactly what happened.
In doing so, he has a mental conversation with the other personalities in Mari’s body. Mari, Fumiko, and Isao all converge here, coming to terms with how exactly they came to be, and what they want to do next. Mari, the “core” personality, expresses nothing more than her desire for it all to stop, for it all to end. However, thanks to support from Isao and Fumiko, she is able to take a step forward, taking control of her own body, accepting what happened, and coming out a stronger person for it.
However, in doing so, Fumiko and Isao are depicted as leaving, with Mari being the sole remaining personality. Scared, worried, Mari asks, confused, why are they leaving? Weren’t they going to be in it together?
Their response?
Mari is able to go on, as the final chapter of the manga depicts her graduating high school, happy to go on living life as well as she possibly can. Hinting that she is very well aware of her past now, as well as the existence of her alternate personalities, the story ends on this very open-ended note.
And well, considering how Dissociative Identity Disorder is treated in real life, this ending is actually one of the best I’ve seen.
What is important to consider, is that alters, naturally speaking, are not completely misguided, “wrong” parts of the personality. They don’t need to be eliminated or treated, like many other mental illnesses might be. Rather, alters in DID are treated far more as parts of the self, which is why “integrating” these parts of the personality into one concrete whole, is emphasized as so important.
Lo and behold, we see Mari at the end of the series, as a more whole person–someone who has not said goodbye to her alters, but has acknowledged them as a part of herself. She’s still going by the name “Mari,” acknowledging who she is in the present, but Fumiko, Isao–they’re still, most definitely, real parts of herself.
And so, the story of Mari is a very unique one: a story that rather accurately presents Dissociative Identity Disorder, and how these alternate identities can change everything in a person’s life. It’s a story of how a person learns to live their life, moving on from a history that served to disregard them entirely. And man, it’s a story of learning about yourself, constructing your personal identity, presented in a way that is… quite a trip, to be honest.
It’s pretty interesting to say the least.
Well, if I got anything wrong about DID, feel free to let me know in the comments–I’m only a fledgling Psych major after all.
And of course, if you’ve got any thoughts on the manga, or on this analysis, let me know!
This is so interesting. i watched the drama instead but it was insightful getting another perspective of it
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Honestly, I didn’t even know there was a drama! I’m glad you found my commentary interesting, now I’m curious about the contents of the drama haha.
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Literally just finished this manga, and I thought it was gonna be some cliche “guy in girl’s body, gross, kinky teehee” thing, and halfway through I couldn’t believe what I was seeing… an actual depiction of DID. I’m glad I found this so I didn’t feel like I lost my mind coming to this conclusion!
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