"Baku really resembles Suho" — Park Ji-hoon reflects on Weak Hero Class 2 cast changes, reasons Si-eun’s action downgrade

Netflix’s South Korean thriller series Weak Hero Class 2 continues the story of Yeon Si-eun (Park Ji-hoon), a brilliant but physically vulnerable student who repeatedly defends others from brutal school violence.

On April 28, 2025, OSEN reported that the show's lead actor, Park Ji-hoon was interviewed in Seoul, where he noted that a central point of Season 2 was exploring new friendships, but before filming the sequel, the lead actors didn't get much time to become friends.

"They are actors with very different strengths. In fact, we didn't go into filming in such a close relationship. We didn't start filming with a strong friendship. Season 1 was also so much fun, and the director felt like a close older brother, so we filmed so comfortably."

Park Ji-hoon added that despite being surrounded by a new ensemble of lead actors with their intriguing characters, he couldn't help but admire them. Park Ji-hoon said that the character of Baku resembled Su-ho from Season 1 and wondered which actor would be cast for the part.

"'Baku (Park Hu-min)' really resembles Su-ho. I thought, 'Who else can show that kind of live energy?' and while filming, I felt that they were similar. I tried to express that feeling as well."

"Also, Jun-tae never breaks down even in front of strong people, so I thought that guy was 'Kang-kang-yak-yak.' It's not that he doesn't breaks down just because he's strong, but he's respectable and I thought, 'I would do that if I were him.'"

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Park Ji-hoon shares insights on Weak Hero Class 2 filming and cast

On set, Park Ji-hoon found working with the younger cast energizing. In a candid moment, he described how he could be joking around with the other actors until the cameras rolled, at which point he immediately “switched” into Si-eun. Maeil Kyungjae reported on April 28:

“Even during script readings, the director was surprised how I immediately become Si-eun.”

This in-between has allowed him to bond with Ryeoun, Choi Min-yeong, Lee Min-jae, and the rest, creating a chemistry that comes through in the show. Those off-screen friendships, he notes, translated into a natural group dynamic when they were together on camera.

Park Ji-hoon mentioned how he carefully depicted how Si-eun’s personality changes under the burden of loss in Weak Hero Class 2. He explained that Si-eun in Season 2 carries “the emotions that have piled up” since losing his friend, making him “tougher” and more desperate in fights.

"What I wanted to show differently was the emotions that had built up over the years because of losing a friend, and the feeling that he had become tougher. I studied and thought about Si-eun's fighting style and the things that were different about him over time. It was about the feeling of being possessed by evil, and wanting to stop fighting like this."

In practice, this means Si-eun fights with renewed ferocity – not for glory, but out of sheer will to end the violence. Park Ji-hoon intentionally portrayed Si-eun as reluctant yet driven, focusing on the quiet moments (like clenched fists or a locked jaw) that signal how “tired” Si-eun is of the cycle of bloodshed.

Park Ji-hoon also endured the show’s intense physical demands. He confirmed that despite the brutal fights in Weak Hero Class 2, he never suffered a major injury (“no big injuries,” he said), explaining that they choreographed the stunts so the actors could take hits safely and reset quickly.

Even so, filming has left its mark: for a climactic scene at the end of Episode 8, Park Ji-hoon revealed he actually began crying alongside co-star Lee Jun-young (who plays Seong-je).

"I cried after finishing the program, and Lee Jun-young was next to me. But for some reason, a deep aftertaste lingered. When I saw the last scene, I had one thought: I ran for this scene. While filming, memories, action scenes, sweat, and tears flashed before my eyes. I felt such overwhelming emotions."

Throughout production, Park Ji-hoon said the move from Season 1’s summer-blue palette to Weak Hero Class 2’s colder amber tones (as director Yoo Su-min described) helped him capture Si-eun’s shifting mood. Si-eun is far more brooding this time, often silent and calculating.

Park Ji-hoon shared that he even dieted and trained hard, losing muscle mass, to appear physically weaker and more vulnerable in Weak Hero Class 2, yet his eyes now burn with the character’s repressed despair.

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Weak Hero Class 2 bridges with Season 1's heartbreaking ending and delivers another well-written story

In Weak Hero Class 2, Si-eun arrives at EunJang High still haunted by his experiences from the past. Determined not to lose anyone else, he once again finds himself in the middle of bloody school turf wars. Early in the season, Si-eun is immediately tested: class bully Choi Hyo-man (Yoo Su-bin) and Hyo-man’s underling Seo Jun-tae (Choi Min-yeong) provoke violence.

When Jun-tae tries to steal classmates’ phones to impress Hyo-man, Si-eun intervenes to stop the fight, calling Jun-tae a coward. Hyo-man then attacks Si-eun repeatedly, but Si-eun refuses to stay down.

In Episode 2, Si-eun fights back fiercely, and an ally unexpectedly intervenes: Go Hyun-tak, nicknamed “Gotak” (Lee Min-jae), leader of the school’s basketball team, breaks up the fight and scares off Hyo-man.

This confrontation sets the stage for new friendships. Si-eun forms an alliance with Gotak and, by Weak Hero Class 2 Episode 3, also with Baku (Ryeoun), the strong yet good-natured basketball captain who steps in to rescue them when Hyo-man’s gang attacks.

Meanwhile, Choi Jun-tae – once Hyo-man’s lackey – returns the stolen phones to Si-eun, then is himself beaten by Hyo-man. Si-eun’s timely help causes Jun-tae to “decide to live a braver life” and shift loyalties.

When Life Gives You Tangerines actor Lee Jun-young's addition to the cast as Geum Seong-je, the chaotic, fanatically violent lieutenant of Baek-jin’s Union gang. Seong-je is ruthless and unpredictable; he confronts Si-eun multiple times, including the kidnapping atop the school roof.

Yoo Su-bin as Choi Hyo-man is the main bully with vengeance in Season 2 and instigates conflicts at EunJang High. He is the one who originally beat up Jun-tae in Episode 1, setting the new fights in motion. (Yoo Su-bin was well-known for playing comedic roles in Crash Landing on You and D.P., but here he brings menacing intensity.)

Bae Na-ra as Na Baek-jin, who is the head of the Union, a shadowy gang of students. Baek-jin is one of the best fighters in the area, with a calculating mind and big ambitions. His goal is to bring all of EunJang High (and its students like Baku) under his control. Baek-jin’s quiet menace motivates Weak Hero Class 2’s most dangerous confrontations.

In Season 1, Si-eun began as a model student at his old school, only to be drawn into gang conflicts while trying to protect his friends. Season 1 introduced him as a genius student and a calculating fighter.

By the end of that season, Si-eun’s past trauma—his guilt over failing to save a friend—catches up with him, and he is expelled and forced to transfer. Weak Hero Class 2 picks up his story at the new EunJang High School, where he must navigate even deadlier threats.

Together, Si-eun, Baku, Gotak, and Jun-tae form an uneasy team in Weak Hero Class 2. Their confrontations quickly escalate. They attract the attention of Na Baek-jin (Bae Na-ra), the ruthless leader of a student gang called the Union, and his lieutenant Geum Seong-je (Lee Jun-young).

The final episodes (5–8) further escalate the conflict. Si-eun and his new friends – now facing off against the full might of the Union – navigate traps, betrayals, and alliances. The stakes involve not only physical survival but also Si-eun’s emotional journey.

Si-eun’s challenges in Season 2 are not just bigger fights, but the psychological struggle to move on from loss and keep others safe.

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Weak Hero Class 2 is available on Netflix and continues the tale of Si-eun into a different high school, amidst uncharted territory. Fans are hopeful for a Season 3 renewal due to Weak Hero Class 2's open ending.