The Myers-Briggs® Personality Types of the Weak Hero Characters

There’s something special about a show that makes you want to throw your laptop across the room one minute and knit an emotional support scarf for every character the next. Weak Hero is that show. It grabs you by the collar, slaps you across the face with your own unresolved trauma, and then whispers, “but hey… maybe friendship could save us?” before pushing you into a cement wall of betrayal.

This series isn’t just about school violence—it’s about identity. It’s about what you do when the world turns you into a punching bag (literally or metaphorically) and whether you punch back, shut down, or hire someone else to do the punching for you. As an MBTI® practitioner I couldn’t help but try to profile the characters as I watched them. Some were easy and obvious (looking at you, Ahn Su-Ho), and others were a huge challenge (ugh, Beom-seok).

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The Myers-Briggs® Personality Types of the Weak Hero Characters

PARK HU-MIN — ESFP

If charisma were currency, Baku would be a billionaire with no concept of budgeting. He’s got that warm, open energy that makes you trust him instantly. He’s hilarious, generous, loyal, fun-loving, but also deeply attached to his sense of right and wrong.

As an ESFP, Baku is what happens when Extraverted Sensing meets a moral compass held together by duct tape and childhood trauma. He lives in the moment, reacts in real-time, and throws himself into danger like it owes him lunch money. He’s the ultimate protector.

When injustice shows up, he jumps straight into action. He acts. He picks up a basketball and solves the problem. Is it always the wisest option? No. Is it usually the most Baku option? Absolutely.

He’s the kind of friend who will apologize on your behalf because he knows you suck at apologies, then get suspended from school for wrecking the guy who looked at you wrong, then come back and tell a joke so dumb it makes you snort-laugh in the middle of math class. He’s also the kind of guy who hurts when you hurt. Like, really hurts. Like goes-still-and-can’t-eat-his-rice hurts.

And the tragedy of Baku is that underneath all that sunshine and slam dunks is a kid who knows he’s not the smartest in the room, who knows he can’t solve everything with strength or charm—but he tries anyway. He tries because his heart is too big and his fists are too fast and sitting still while someone suffers is not in his nature.

GO HYUN-TAK — ISTP

Go Hyun-Tak is that rare breed of ISTP who’s equal parts “doesn’t care” and “cares too much.”  He’s practical, reserved, and allergic to bullsh*t. While Baku’s leading the charge, Hyun-Tak’s figuring out the most efficient way to end a fight with minimal emotional fallout and maximal knee-to-gut ratio. He’s not interested in speeches. He’s interested in whether your stance is too open.

But don’t let the calm exterior fool you—Hyun-Tak is feral for his friends. He’ll walk into a death trap without blinking if someone he loves is inside. He’ll fight people twice his size with nothing but a grudge and a good pair of sneakers.

Hyun-Tak has this way of making you feel safe without making a big deal out of it. He doesn’t want applause. He wants peace—and maybe a friendly game of basketball.

But when that peace is broken? When someone he loves is hurt? His fists talk first, and they’re fluent in vengeance.

He’s the kind of guy who will roll his eyes while you cry, then quietly offer you his sleeve. The kind who’ll never say “I love you” but will bleed beside you without hesitation. A boy of few words and even fewer second chances—but once you’re in his circle, you’re in for life.

YEON SI-EUN — INTJ

At first glance, Si-eun is the classic INTJ archetype: quiet, cold, calculating, and absolutely done with human nonsense. His voice rarely rises, his facial expressions hover between “bored” and “judging your entire existence,” and his idea of a good time is solving equations while everyone else is playing dodgeball with their trauma. I absolutely loved him right away and thought he was such an amazing example of the INTJ at their best and under stress.

Si-eun doesn’t lack feelings—he just stores them in a pressure cooker labeled “DO NOT OPEN” until someone hurts his friends or makes the mistake of underestimating him, and then… well. Then he opens the valve. And hell pours out.

INTJs are like this. Outwardly they seem contained, cold, and even detached, but inside they tend to have intense feelings. They’re loyal to what they believe in, who they care about, and what they’re willing to go down fighting for. And that’s ultimately what Weak Hero is all about.

Watching Si-eun plan a fight is always interesting because it’s never what you expect. Each movement is premeditated but unpredictable. Every opponent’s weakness is a variable he’s thought through in advance. He doesn’t punch unless he’s already simulated the outcome three times and chosen the version that ends with him bruised but victorious. If INTJs are known for thinking ten steps ahead, Si-eun is twenty moves in, predicting what you’ll wish you’d done.

But beneath the ruthless logic is a kid who cares—painfully, desperately, inconveniently. He’ll never say it out loud (that’s terrifying), but he’ll risk his body for people who barely know how to say thank you. He’s not in this fight because he enjoys it. He’s in it because walking away would violate every single fiber of that titanium-wired internal code of his.

And when he breaks? Well, then everyone better watch out.

Si-eun in extreme stress falls into the grip of his inferior function, Extraverted Sensing (Se). If you don’t know what that means, you can find out more here. Basically it means he loses touch with his long-term, abstract focus and becomes more impulsive, reactive, and reckless. His Se grip moments are horrifying and heartbreaking. All that pent-up rage and helplessness, all that loneliness, channeled into brutal, chaotic violence. Not because he wants to, but because his system can’t handle any more betrayal, and he needs something—anything—to crash.

Si-eun is the hero because he shows up, even when it costs him everything, even when people think he doesn’t care. He’s a kid who didn’t ask for this war, but once he’s in it, he will not back down. He’ll fight with fists, with strategy, with sheer intellectual fury—until the people he loves are safe, or he’s too broken to keep going.

GEUM SEONG-JE— ENTP

Seong-je walks into a room like he’s already imagined six ways to burn it down and is just deciding which one would be the most fun.

He is pure chaos in a school jacket, the human embodiment of “what if Loki had a vape and unresolved trauma.” He smiles like a shark, fights like it’s foreplay, and treats life like a video game where he has infinite respawns and no morals slider.

As an ENTP, Seong-je lives in a world of improvisation and possibility. He’s ultimately here to play. And if someone else gets hurt in the process? That’s just a narrative twist.

Seong-Je doesn’t crave power so much as disruption. He wants to stir the pot, watch the fallout, and make a snarky comment while everything burns.

But, as with most Thinking types,—he feels more than he lets on. That moment when Baek-Jin thought the worst of him and didn’t ask him how he was feeling? That created a lot of animosity and bitterness. Because underneath the cocky smirks and mind games is a boy who chose loyalty, got screwed, and now feels rejected and wants to shake things up for Baek-jin just to make him squirm.

Seong-je is the kind of guy who will destroy your entire self-concept with a grin, then offer you a cigarette and a half-sincere compliment. He thrives on unpredictability, but deep down, you get the sense that he wanted something to hold onto—he just gave up on finding it.

AHN SU-HO — ESTP

Ahn Su-Ho is the guy who makes you feel safe just by showing up. Like, if the world’s ending, you want Su-ho there—he’ll crack his knuckles, give the apocalypse a withering side-eye, and say, “Not today, man. Not on my shift.”

As an ESTP, Su-ho is Extraverted Sensing with a soul. He lives in the now—not in a self-destructive thrill-seeking way (well… maybe a little), but in a “why are we talking about feelings when I can handle the problem” kind of way. He’s action-first, but not heartless. If anything, he’s got too much heart for his own good.

Su-ho doesn’t do abstract philosophies or long-winded conversations about morality. But if you’re being hurt, he will move. No long-winded speeches. No analysis. Just pure, instinctive, protective presence.

He was raised by his grandmother, and feels a deep sense of responsibility to live up to her expectations. That’s why he fights like he’s got something sacred to protect. Because he does. Whether it’s his grandma, his friends, or just the fragile concept of justice in a world held together by violence and bureaucracy, Su-ho fights for it.

Another thing about Su-Ho is he has zero tolerance for foolishness. When I was watching Beom-Seok’s downward spiral and Si-eun and Su-Ho’s reaction to it, I kept thinking of myself (INTJ) and my husband (ESTP). ESTPs haaate foolishness, emotional over-reactions, and betrayal, especially betrayal based on some unfounded, confusing, unverifiable feeling.  Su-Ho has no patience for Beom-Seok when he’s spiraling. Yeah, Beom-Seok might have a tragic back story, but that’s no excuse for stupidity. Meanwhile, Si-Eun is trying to guess the pattern and get into Beom Seok’s perspective (Introverted Intuition at work). My husband and I both laughed because the two character’s responses to Beom-Seok reminded us so much of ourselves when we’re dealing with difficult people.

What makes Su-ho so compelling is that he’s a fighter who doesn’t want to fight. He doesn’t revel in dominance. He just knows he’s the only line of defense between the soft people he loves and the chaos trying to eat them alive. And even though he’s tired—bone-tired, soul-tired—he still stands up for them.

You want to believe in people after watching Su-ho. You want to believe that strength and kindness can exist in the same body. He reminds you that not all heroes wear capes. Some wear backpacks and beat up your bullies after school.

OH BEOM-SEOK — Probably ISFP or INFJ (Unhealthy as Hell Either Way)

Okay. Here we go. You might need to grab a stuffed animal for emotional support, because Beom-Seok is a slow-motion implosion wrapped in a cardigan. I went from loving him to hating him to loving and hating him simultaneously.

Typing Beom-Seok is like trying to diagnose a ghost in the middle of its haunting. You see the flickers of who he might have been. You feel the echoes of a gentle, soft-hearted kid who just wanted to be safe. But the longer you watch, the more that softness hardens into something jagged and dangerous and heartbreaking. And the worst part is, you understand it.

Whether Beom-Seok is an ISFP crushed under shame and alienation, or an INFJ whose Ni got hijacked by trauma and turned into a doomsday prophecy only he believed—either way, he’s what happens when someone sensitive gets shoved into a world that doesn’t just ignore their pain, it weaponizes it.

I could see a good argument for Beom-Seok being an ISFP. He’s absorbed in his own subjective feelings and rarely airs them, just lets them simmer. This is the root of some of his problems. If he would just open his mouth and express his vulnerability everything could have gone so much better for him. Instead, he let his feelings devour him from the inside. On top of that, he makes intuitive leaps and assumptions regularly, which could point to tertiary Introverted Intuition. He’s also impulsive and reckless, which could point to unhealthy Extraverted Sensing. That said, he rarely  leaps into action himself, instead he often finds someone else to do it.

I could also see an argument for unhealthy INFJ. Beom-Seok makes intuitive leaps based on small bits of data (Su-Ho not following him back, for example) and then follows them blindly. He chameleons himself in order to find his people, even when he knows they are taking advantage of him. He also seems to have a strong reaction to stress that involves recklessness, impulsivity, spending, drinking, and rage. This could point to a Se-grip response, which is something that INFJs grapple with during chronic or extreme stress.

The problem is, there’s not enough data for me to responsibly make a decision on Beom-Seok. I’ve seen arguments for INFP, but I can’t see any evidence of Beom-Seok having Extraverted Intuition. He doesn’t theorize, he trusts his one solution fairly quickly (paying off Gil-Su, hiring an MMA fighter to beat up Su-ho, etc,.).

He’s all defense mechanism. He spends the whole show trying to construct some version of himself that will finally be lovable—finally untouchable. At first, he thinks he can buy loyalty with money. Then he tries mimicry—be like Si-eun, be like Su-ho, maybe then they’ll see him. But what they see is the cracks.

And Beom-Seok knows they see the cracks.

What makes his arc so brutal is that nothing truly cataclysmic pushes him over the edge. It’s death by a thousand paper cuts:

• A missed Instagram follow-back.
• Being asked to pay (again).
• A seat too far from the center of the group.

To someone more stable, these things wouldn’t even register. To Beom-Seok, they’re confirmation. Evidence of what he’s always feared: that no one will ever love him unless he makes them. Unless he owns them. Unless they fear him more than he fears the world.

You never stop seeing the scared kid in his eyes. That’s what makes it so hard to hate him. Even at his most monstrous, part of you wants to shake him and scream, “You didn’t have to do this! You were loved!” But he never believed that. Not enough. Not in time.

NA BAEK-JIN — INTJ

If Yeon Si-eun is what happens when an INTJ decides to protect the world with brains and bruises, Na Baek-Jin is what happens when an INTJ decides the world isn’t worth protecting unless it kneels.

I’m still bitter that I don’t have more answers about Baek-Jin after finishing Season 2. WHY WERE THERE NOT MORE ANSWERS?!?! Did anyone else feel completely deflated and miserable at the end? If so, tell me in the comments. I need solidarity.

Baek-Jin is not here to perform dominance like the other thugs throwing fists for clout. He’s the one who sent them. The one watching from the shadows. The one already two moves ahead and halfway through dismantling your future.

INTJs don’t need approval—they need results. And Baek-Jin has spent his entire life learning how to get them. At any cost.

But the tragedy—and there’s always a tragedy with INTJs and K-drama villains—is that he didn’t start out cold. There was warmth once. There was friendship. There was Baku. And when Baku left the Union, Baek-Jin lost his anchor. He lost the one person who might have convinced him to walk away from the monster he was becoming.

Instead, he doubled down. Hardened. Rationalized. Calculated. Turned his longing into leverage and his love into liability.

Baek-Jin’s Fi is buried so deep beneath layers of Ni-Te scaffolding that by the time we see it—through those flickers of regret, the hesitation when Baku looks at him like he used to—it’s already too late. He’s built the machine, and now the machine is eating him.

SEO JUN-TAE — ISFJ

Seo Jun-Tae is the guy who shows up with ointment and magnesium when everyone else brings fists. Who buys your meds, watches your back, and says things like “be careful” and really means it. I mean, someone around here has to care, and no one else remembered.

As an ISFJ, Jun-Tae is the embodiment of quiet courage. He may not start the fight, but he’ll observe and look for the right moment to swipe someone over the head with his backpack. He’s always there. Watching. Noticing. Holding things together with quiet gestures and small acts of defiance, like sneaking information, distracting bullies, or shielding a friend with his own very breakable body.

He’s not the main fighter. He’s not the strategist. But he’s the glue. The one you look for in a crisis. The one who holds your hand without making it weird. The one who remembers your bruises and brings snacks.

JEON SEOK-DAE — ISTP

Seok-Dae is the kind of guy who looks like he doesn’t care, sounds like he doesn’t care, and then suddenly breaks someone’s nose for messing with the one person he actually cares about.

Quintessential ISTP: stoic exterior, deadly precision, loyalty buried so deep it’s practically classified.

He’s not in Gil-Su’s gang because he’s power-hungry. He’s there because he understands the math of survival. Aligning with danger is sometimes the only way to shield the people you’d take a punch for, especially when the world doesn’t reward quiet protectors.

Seok-Dae is always calculating and analyzing the situation. You can see it in his eyes and the way he observes what’s going on around him, gauging what his leverage point is going to be and whether or not he still agrees with what he’s doing. He tolerates violence like a necessary evil, but you can tell he’s not really enjoying himself.

YEONG-I — ESFP

Yeong-i is the kind of girl who’ll flirt with you, sass your enemies, and then swing a chair at someone twice her size if you so much as look at her friends wrong.

She’s an ESFP who is making the most of the pretty awful hand she’s been given in life. Whatever the case, life is happening now, and she’s going to live it, even if it means crashing headfirst into a gang of psychos with nothing but guts and a grudge.

Yeong-I is bold and sensitive in equal measure. I would have liked to see her again in Class 2 and was pretty disappointed that she didn’t show up again.

JEON YOUNG-BIN — Unhealthy ESFJ

Young-bin doesn’t crave control. He craves applause.

He wants to be feared, sure—but more than that, he wants to be admired. He wants to be the guy everyone cheers for, the guy who walks into a room and has the emotional weather bend to his mood. That’s unhealthy Fe in overdrive—tuned to everyone else’s reactions, but not to connect. To dominate the vibe.

I’ve seen most people type him as an ESTJ, but that tends to happen. People see “dominating bad guy” and think ESTJ (or ENTJ). The truth is, bad guys can come in all flavors and types. Ultimately, Young-Bin isn’t logically detached and analyzing how to reach a particular impersonal objective. No. He’s all about performing. His bullying is theatrical, crowd-tested. Everything he does is about emotional impact: “Did they look scared enough? Did they thank me for backing off? Does my mom still admire me?”

This is a kid who builds his whole self-image on how other people reflect him back. And when that mirror cracks—when people stop reacting the way he wants—he lashes out harder. Crueler. Louder.

Deep down, he’s fragile. He needs the crowd because without it, he doesn’t know who he is.

So he keeps twisting his Fe—using it to control and manipulate. Not to nurture, but to feed the gnawing fear that maybe, deep down, no one actually likes him.

What Do You Think?

Do you relate to any of the characters here? Do you have any different perspectives on their personality types? Let me know in the comments!

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