MBTI typings + analysis of weak hero class characters
disclaimer: this analysis would be based on cognitive functions, so please don't tag this post with "why is he an e, he should be an i" or something like that. please read about cognitive functions, it's life-changing.
and this is my personal observation and analysis, so i'm not claiming 100% accuracy. but i have been studying mbti typology for 5 years, and i believe my hyperfixation on weak hero characters is strong enough to offer an interpretation that's atleast in the right ballpark. feel free to share your own opinions, though.
yeon sieun — INTJ (Ni-Te-Fi-Se)
INTJs lead with introverted intuition (Ni), which means they're constantly absorbing patterns and projecting outcomes. that’s essentially sieun’s entire combat strategy. he fights with foresight, not force. his brain is always several moves ahead, calculating silently before acting. he also has auxiliary extraverted thinking (Te), which makes him prioritize efficiency. this explains why he’d rather stab someone with a pen and end the fight cleanly than try to brawl with someone much stronger than him. it's just more efficient.
INTJs have tertiary Fi (introverted feeling), which acts like a quiet internal moral compass. it’s always there in the background, nagging him. it's not loud enough to dictate his decisions, but still present in case he changed his mind. that’s why he hesitates to help juntae at first. not out of apathy, but because the voice in his head keeps getting suppressed by his dominant intuition, which keeps telling him to mind his own business. it keeps warning him of the consequences of getting involved. however, he takes action when he finally listens to his tertiary Fi telling him, you know it’s the right thing to do.
his inferior Se (extraverted sensing) makes him inattentive to his physical environment unless it directly interferes with his internal world. he's never interested or notices people around him, unless his peace is disrupted. a blatant example of this is when he completely misses seongje showing up at suho’s hospital. he doesn’t register what's happening around him until it directly concerns him.
he’s also emotionally private (typical INTJ trait — they don’t like performing vulnerability). sieun is more expressive in his unread text messages to suho than he ever is face-to-face. it's a classic Ni-Fi wall - he feels deeply, but processes everything internally, where no one can touch it.
ahn suho — ESTP (Se-Ti-Fe-Ni)
ESTPs are sensor-thinkers, grounded in the present and driven by logic. suho’s dominant Se (extraverted sensing) makes him highly reactive to his environment. he only intervenes when he senses something is wrong. it’s not moral obligation, and definitely not out of concern for consequences. his instincts are fast, physical, and attuned to danger. we see this in his professional fighting skills (MMA trainee and all) and athletic abilities. it's also obvious in the way he expresses love through action, taking on tiring jobs for his grandma without complaint, teaching sieun how to fight. it's a typical Se expression of love - fixing, serving, fighting, guiding.
his Ti (introverted thinking) is what makes him sharp. he’s logical and objective, but not necessarily fair, because he's not led by morals (which doesn't mean that he doesn't have morals at all, but it's not the driver of his decisions). he's loyal to who he cares about, not to any sense of abstract justice. like how he’ll go to hell and back for sieun, but probably won’t extend that same energy to everyone (this can be backed up by sumin pd, who pointed out that unlike baku, who protects the whole school, suho only protects sieun. baku has a higher moral compass, as a high Fi-user, but more on that later). his humour is also very Ti-coded; dry, clever, and often rooted in logic ("how can you talk about food while eating?" "you talk about life while living it").
tertiary Fe (extraverted feeling) gives him just enough charm and emotional fluency to read a room, crack a joke, or comfort someone. but it’s also fragile. he gets defensive fast, especially when misunderstood or unfairly blamed (like how he gets physically aggressive when beomseok starts beefing with him for no reason). weak Fe makes him take criticism personally and lash out emotionally.
he also has inferior Ni, which means his intuition is weak, and he rarely thinks ahead. like when he gets into gilsu’s car without a solid plan. he improvises well (texting sieun from his watch), but forgets to consider that gilsu could check his phone too.
oh beomseok — INFP (Fi-Ne-Si-Te)
beomseok runs almost entirely on introverted feeling (Fi), a deeply internal moral compass that tells him this is right even when it objectively… isn’t. healthy Fi stands for staying true to your values and beliefs. unhealthy Fi becomes a justification engine. and beomseok's Fi has been warped by years of trauma. that’s how he goes from offering to pay suho to save sieun from bullies to wanting to destroy suho for betraying him. he does what he feels is just. the line between good and evil becomes how do i feel about it, and the trauma twists those feelings into something darker.
his Ne (extraverted intuition) gives him imagination and ideas, but unhealthy Ne (again, due to trauma) creates spirals, such as overthinking, projection, and paranoia. like how he starts believing that suho and sieun were replacing him with youngyi.
tertiary Si (introverted sensing) makes him cling to what’s familiar. people with low Si are scared of unfamiliarity. that’s why youngyi’s addition to their group unsettles him. to him, she disrupts the group dynamic he’s grown attached to.
his inferior Te (extraverted thinking), the logic function, is like a faint alarm bell in the back of his mind, whispering this won’t end well, which is why he often has moments of hesitation. but his dominant Fi drowns it out. he has to stick to his sense of justice cause he knows best. or thinks he does.
youngyi — ESFP (Se-Fi-Te-Ni)
youngyi leads with dominant Se, paired with Fi — which means she lives in the moment, feels things deeply, and owns it. she’s unapologetically herself, unbothered by rejection, which is exactly the kind of ability that gets her to befriend someone as guarded as sieun. she isn’t intimidated by anyone. she's grounded in the present, quick to act, and physically assertive, often responding to situations with bold, instinctive energy.
what sets her apart from suho (who's also an Se-dom), though, is that her actions aren't filtered through detached logic (Ti), but through a strong internal value system (auxiliary Fi). she doesn’t analyze her choices with practical calculation, she feels her way through them, led by what resonates with her personally.
but Fi also governs identity. so when beomseok accuses her of ruining the group, and essentially causing suho’s coma, it shatters her. she doesn’t just feel attacked, she feels like her sense of self is broken. that's why she disappears from everyone's lives, because how can she face sieun, when she can't face herself? that’s the danger of Fi - when it internalizes blame, it takes everything personally.
park humin (baku) — ENFP (Ne-Fi-Te-Si)
ENFPs reflective yet spontaneous personalities with a strong internal value system. baku is no exception. his auxiliary Fi makes him emotionally honest and morally anchored, but his dominant Ne keeps his mind in motion, always bouncing between possibilities, fears, and imagined futures. that’s why he hesitates to fight again because what if someone gets hurt again? but when something triggers his core values (Fi), when someone he loves is in danger, he acts out. consequences be damned.
he jokes around to defuse tension, but he's deeply intuitive, emotionally attuned, and cares more than he lets on. it’s why he’s one of the only people who can get someone like sieun to open up, by simply being emotionally available, non-judgmental, and real. people with high Fi connect well with people they can relate to, which is why baku and sieun form a strong bond early on.
while his high Fi gives him access to vulnerability, it also acts as a strong boundary. he refuses to work with baekjin, despite his history with him, because it violates his sense of right and wrong, because baekjin brutally hurt gotak and ruined his career, which is unforgivable. he only crosses that boundary when threatened and forced.
baku’s tertiary Te is blunt, explosive, and reactive, especially under stress. it acts before planning. when stressed, he grabs for Te, takes charge, punches first, thinks later. his Fi follows his own moral compass. he refuses to fight and preaches non-violence. but when people precious to him are hurt, he can go and far beyond his self-drawn boundaries.
seo juntae — ISFJ (Si-Fe-Ti-Ne)
juntae is the emotional backbone of the group. ISFJs are built to nurture, and his Fe (extraverted feeling), paired with Si (introverted sensing), makes him deeply attuned to others' emotional needs. he notices sieun skipping meals, withdrawing, and not sleeping. his Si gives him observational memory; he tracks patterns and changes, then responds with quiet care.
he’s the only character with strong Fe in the whole cast, which is why he's the only one who genuinely hates conflict, and is the peace-maker of the gang, readily resolving misunderstandings and arguments between his friends. Fe also gives him strong empathy, which is what makes him slow to judge. he can easily read tone and emotional behaviour. it’s why he doesn’t believe sieun when sieun lies and says he doesn’t want to be friends anymore, because he knows it’s not true. he’s the one who tells both sieun and bakugotak that the other doesn’t mean what they’re saying.
Fe + Si makes him the one person who understands without demanding. he’s the first to tell sieun, "it’s not your fault," because he knows it will help. and yet, he holds grudges. because Si doesn’t forget. that’s why he refuses to forgive hyoman, even after he joins their side.
go hyuntak (gotak) — ESTP (Se-Ti)
this might be a controversial take since gotak is often typed as an ISFP, but i see a strong mix of Ti and Se in how he operates. in my opinion, he’s an ESTP; he’s an active, physical, and analytical thinker. he’s impatient, yes, but also deliberate. he observes, processes, then acts, like when he tells juntae to escape before counting opponents in the underpass fight with seongje, or when he decides to fact-check the rumor that sieun wants to fight him instead of reacting right away.
his Se is undeniable: he’s aggressive, athletic, and always grounded in his body. even after quitting taekwondo, he stays physically engaged, taking up basketball, aggressively skipping rope despite his bad knee, because “he has to do something.” that’s textbook Se: movement as expression. like suho (another high Se user), gotak communicates care through physical action; teaching juntae to fight, teaching sieun how to play basketball, physically lashing out when hyoman insults baku, or breaking into the union garage when baku disappears, even though sieun asked him not to. he acts because he has to: Ti wants clarity, Se wants momentum.
he has low Fe, which means he has empathy and the ability to understand emotional cues, but his emotional communication is clumsy (like how he needs baku to prompt him to apologize or say thanks to sieun). His Ti strives to stay calm and factual, but his emotions; protectiveness, irritation, and loyalty — simmer just beneath the surface. he doesn’t judge quickly (a sign of Fe-awareness), like how he defends sieun from rumours despite a rocky first impression of him. still, like suho, he lashes out when he feels misunderstood, like when he says cruel things to sieun during their fallout. And with low Ni he rarely plans far ahead; he makes impulsive decisions. like breaking into the garage wasn’t a plan, just his Se-impulse running full speed.
geum seongje — ENTP (Ne-Ti-Fe-Si)
this is really the easiest one to type because seongje is a textbook ENTP: chaotic intellect.
dominant Ne makes him erratic, unpredictable, and dangerously flexible. he's constantly probing, experimenting, and testing limits. people are like a puzzle to deconstruct. Ne is the function that gives you the skill and urge to explore multiple possibilities, which explains how seongje can justify switching sides mid-fight if it feels fun. he'd join his enemies, then betray them for the punchline.
his tertiary Fe doesn’t function like suho or gotak’s, who pair Fe with Se. while suho and gotak are highly reactive and defensive over them/their loved ones being insulted or misunderstood, seongje’s Fe is more detached. he treats insults like jokes ("is it fun playing na baekjin's minion?" "it is fun. i get to beat up losers like you.").
his Fe makes him socially aware, but it's not exactly a strength, it's weaponized. he understands emotional tones, social roles, and twists them to provoke or entertain. he mocks sincerity (like how he laughs at gotak over his protectiveness for juntae) but still craves attention and reaction (feels hurt because baekjin didn't ask him if he was okay after fighting with sieun).
so ENTP makes seongje unpredictable, perceptive, and always a step ahead.
na baekjin — ENTJ (Te-Ni-Se-Fi)
baekjin, as an ENTJ, is essentially a more dangerous, volatile version of sieun. he's smart, strategic, and ruthlessly efficient; a master planner who relies on his introverted intuition (Ni), to forecast outcomes and his extroverted thinking (Te), to execute them with precision. to baekjin, efficiency isn’t just useful; it’s everything. he doesn’t waste time on what feels good or what’s morally right, only what gets results.
but his inferior Fi (introverted feeling) means he lacks the internal framework to process emotions authentically. he struggles to recognize emotional nuance, both in himself and in others, which leaves him disconnected from his own vulnerability. that’s why, instead of just saying “don’t leave me,” he orchestrates emotional hostage scenarios (like threatening to hurt people) to keep baku close. it's twisted, but, to him, weirdly efficient. and in baekjin’s world, effectiveness often replaces intimacy.
he knows what works, not what's right. he weaponizes logic without empathy. and you can’t out-think him, because he’s already seen your next ten moves and calculated exactly where you’ll land.
baekjin uses control and intelligence as a shield, mastering manipulation to avoid vulnerability.
so that ends my analysis. if you need a detailed analysis of a specific character, have contrary opinions, questions about mbti, or need any clarification, then leave me an ask!
