You may know him as the “Hak-ssi” uncle from When Life Gives You Tangerines. In the webtoon, he might be the deadliest of the three — and he does it all with his feet.
The last of the three fathers in Agent Kim Reactivated is a mild neighborhood taekwondo instructor, teaching kids how to kick. Fifty years old. Gentle-looking, seemingly the furthest thing from a fighter.
He may also be the most dangerous man of the three. He disarms an armed agent from South Korea’s intelligence service barehanded. His own son — a fighter who competed at the professional level — can’t land a single hit on him. This is Seong Han-su.
And for Korean viewers, there’s another layer to this character: the actor playing him, Choi Dae-hoon. He’s the “Hak-ssi” uncle from When Life Gives You Tangerines.
This covers material from the original webtoon. The drama may take a different path.
From “Hak-ssi” Uncle to Taekwondo Master — The Choi Dae-hoon Reversal
If you watched When Life Gives You Tangerines (폭싹 속았수다), you’ll remember Choi Dae-hoon. He played Bu Sang-gil — the petty, sharp-tongued local bully of Dodong-ri who barked “Hak! Ssi” at every setback. Contemptible, mean, and yet impossible to hate — a scene-stealer who spawned his own memes.
Here, that same actor stands at the opposite end. Seong Han-su, a former taekwondo gold medalist. On the surface he runs a white-walled taekwondo studio teaching neighborhood kids, but he’s a former operative who once ran missions between life and death.
From Bu Sang-gil to Seong Han-su — that range is the whole story of Choi Dae-hoon. An actor who spent more than twenty years in supporting roles, as a scene-stealer, close to anonymous, finally arriving at his moment. It’s why Korean audiences welcomed the casting.
Where He Came From — The Gold Medalist of Viral Hit
Seong Han-su originally comes from the webtoon Viral Hit (싸움독학), the story of a bullied boy who teaches himself to fight through YouTube videos — one of the flagship titles of the Park Tae-jun Universe. Netflix adapted it into a Japanese live-action drama released in 2026.
In that world, Seong Han-su is introduced as a former Olympic taekwondo gold medalist. The interesting part: he isn’t a mixed martial artist. No hand techniques, no grappling. He reached the top tier of the entire universe on taekwondo kicks alone. In his younger years, his combat ability was said to rival that of his friends Kim Bujang and Park Jin-cheol. The drama’s choice to cast him as a “taekwondo gold medalist studio owner” carries that original core straight over.
How Strong Is He — Strength Proven in Scenes
Seong Han-su’s strength is proven not in words but in scenes.
The first time he shows his hand in Manager Kim, a squad of armed government agents descends on him. Seong Han-su doesn’t throw a single hand strike — he sweeps them all with kicks, then walks out at a leisurely pace beside Kim Bujang. One of the agents watching says it: this is a man important enough that North Korea once tried to recruit him.
The high point is his fight with Kang Guk-cheol, an agent from the NIS — South Korea’s national intelligence service. Kang comes armed with a pistol and a knife, firing on him. Seong Han-su dodges every round without taking a single hit. Then he subdues Kang with kicks alone, finishing with a 1440-degree spinning kick that levels him. That one scene establishes Seong Han-su as a fighter who comfortably surpasses the top-ranked figures of Viral Hit.
His own son is no exception. Seong Tae-hun is a fighter who reached the professional MMA stage and ranks among the near-strongest in this universe. And yet, when that son faces his father, he can’t lay a finger on him — he’s dominated one-sidedly. Even when the father pushes him, warning him to fight seriously because he could die, the son is reduced to simply blocking.
How He Fights — Only His Feet
What makes Seong Han-su’s combat distinct even among the three fathers is its purity.
Kim Bujang removes targets silently with wire and assassination technique. Park Jin-cheol takes on an entire battlefield with C4 and firepower. Seong Han-su uses no weapon, no firepower — not even his fists.
Only his feet.
He barely uses hand techniques. No grappling, no punches. He drops every opponent with Olympic-style taekwondo — the kick-focused kind you see at the Games — alone. In a universe that measures power by how many rotations a kick carries, his exceed 1440 degrees. At 360 degrees per rotation, that’s more than four full spins in the air before impact — a physically impossible number, which is exactly the point.
He reacts before an opponent has even begun to move, and shows reaction speed beyond human limits in the face of gunfire. Under the condition of one-on-one unarmed combat, almost no one in this universe can beat him.
The drama’s decision to pin him down as a “taekwondo gold medalist” connects directly to this. In the original too, he rose to the top on taekwondo alone. A kick — a weapon whose power reads instantly on screen — is about as good a setup as you could ask for when translating to live-action.
The Personality Patch — The Stronger He Gets, the Less Human He Becomes
This is where Seong Han-su becomes both the strongest and the most terrifying figure in the universe.
Seong Han-su has a unique trait called the Personality Patch. In his youth he was a nearly feral, violent man. Under a master’s mental discipline, he suppressed that nature to become the gentle instructor of today. So his personality is given a percentage. At rest, it sits at 100 percent — calm and controlled.
But when rage builds or an old trauma is triggered, that number drops. And his combat power rises explosively in direct proportion to how far it falls.
Watch what he does at each threshold.
Personality 34% — He casually slips the attacks of Kim Bujang and Park Jin-cheol, who are trying to restrain him, then blasts both friends away with a single kick. Park Jin-cheol, who always wears a grin, strips the smile from his face and says it: no one can stop Seong Han-su in this state.
Personality 8% — He faces the top-tier villain “King.” Down to eight percent, he makes King cough up blood with a single kick, then breaks King’s arm bone with a kick well past 1440 degrees.
As the number drops, it isn’t his old personality that returns — it’s his reason itself that vanishes. Running wild with no distinction between friend and foe, there is only one thing in this universe that can stop him.
A phone call from his wife.
The man who was raging out of his mind returns to himself the instant he hears his wife Lee So-hyeon’s voice. Devoted husband that he is, he even answers in a trembling voice. The stronger he becomes, the more of his humanity he loses — and a loved one’s voice brings him back to being human. The emotion running through this entire “father universe” is compressed into this one man.
Can the Drama Pull Off This Webtoon Strength?
Here’s the real question.
Dodging bullets with kicks, breaking a man’s arm with a four-rotation kick, combat power that scales with a rage meter — all of it is possible because the medium is a webtoon. A comic can express rotation count, a personality percentage, all of it, through a single look in a character’s eyes.
Live-action is different. The actor’s body has to sell the force of a 1440-degree kick, and the audience has to naturally accept a fantasy rule where a falling personality number makes him stronger. Handled poorly, it turns childish. Handled well, it becomes this character’s most striking weapon.
In that light, casting Choi Dae-hoon is intriguing. In When Life Gives You Tangerines, he carried a single character from his thirties to his sixties on his face alone. If any actor can render the subtle turns — from gentle instructor to a fighter running wild, and back again at the sound of his wife’s voice — through expression, then Seong Han-su’s Personality Patch may not stay a webtoon-only conceit.
The last of the three fathers. The most dangerous man wearing the quietest face. How far the drama chooses to show this strength is the reason to keep watching this character right now.
Basic Info
- English Title: Agent Kim Reactivated
- Korean Title: 김부장 (Kim Bujang)
- Character: Seong Han-su (성한수) — taekwondo gold medalist, owner of the White Taekwondo studio
- Actor: Choi Dae-hoon — “Hak-ssi” uncle Bu Sang-gil in When Life Gives You Tangerines
- Webtoon origin: Viral Hit (싸움독학)
- Network / Streaming: SBS / Netflix (simultaneous)
- Cast: So Ji-sub, Choi Dae-hoon, Yoon Kyung-ho, Joo Sang-wook, Son Na-eun, Kim Sung-kyu
- Original Webtoon: Manager Kim, part of the Park Tae-jun Universe (available in English on Webtoon)
New to Agent Kim Reactivated? Start here first.
Agent Kim Reactivated: What You Need to Know Before You Watch
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Who Is Code Name 66? Manager Kim’s Backstory Explained
Meet the war machine behind the smile.
Agent Kim Reactivated: Who Is Park Jin-cheol, the “God of War”?
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Agent Kim Reactivated: The Three Legends — Who Is Actually the Strongest?
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Anything about Seong Han-su you want to dig into further? Drop it in the comments — I’ll answer, or fold it into the next post.
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