Han So-hee, left, stars as Yoon Chae-ok, and Park Seo-jun as Jang Tae-sang in Netflix new original series "Gyeongseong Creature." Courtesy of Netflix

Netflix's original series, "Gyeongseong Creature," which delves into Korea's painful history during Japanese rule (1910-1945), faced significant delays. Many actors were initially hesitant to take part in a project that highlights Japan's historical wrongdoings, fearing potential repercussions on their careers in that country.

However, the lead actors of the new series, Park Seo-joon and Han So-hee, said they did not hesitate to join the project.

"Throughout my 10-plus-year career, I've yearned to be a part of a project that captures that historical era. Just as I was eager to explore a period genre piece, I encountered 'Gyeongseong Creature.' The fusion of a historical series with the creature genre felt remarkably distinct. I was intrigued by the prospect of portraying a character living in that era," Park said in a recent interview with The Korea Times at a cafe in Jongno District, Seoul.

"I don't chase popularity. I'm simply grateful to those who enjoy the work I do. While people around me may have had concerns when I joined the series, personally, I didn't have any such worries," the actor said.

Park Seo-jun plays dandy bachelor Jang Tae-sang in the new Netflix series "Gyeongseong Creature." Courtesy of Netflix

Set in Gyeongseong, which is the old name for Seoul, the 10-part historical action series follows the city's most eligible bachelor Jang Tae-sang (Park) and a sleuth named Yoon Chae-ok (Han), who sneak into a hospital to find missing people. Jang is searching for a geisha, while Yoon is trying to find her mother.

In the hospital, the two discover that the Japanese army has been conducting covert biological experiments, leading to the creation of monsters.

The series is led by director Chung Dong-yoon, whose previous works include the hit series "It's Okay to Not Be Okay"(2020) and "Hot Stove League"(2019), and is scripted by Kang Eun-kyung, who wrote "Dr. Romantic" series.

"There have been works about Gyeongseong in the past. So I didn't give much thought to doing a story about this era. I really enjoyed 'Hot Stove League,' and I heard director Chung will be leading ('Gyeongseong Creature'), and writer Kang, who cares about me like her own child, is also involved," Han recalled.

"For me, doing a piece is about working with people, so I can't work on a project if I don't like the people. There was the director who I admired and a writer I loved. And Park is an actor I've always admired, so there was no reason not to do it."

Han So-hee plays the role of a sleuth in the series "Gyeongseong Creature." Courtesy of Netflix

Both actors immersed themselves deeply in the historical context to bring authenticity to their roles, considering that the series is set against a backdrop of actual history.

Park shared that he concentrated on portraying the resilience of people living in the challenging era under harsh oppression.

"I think it's a painful history that carries weight and is not something to be ashamed of. I believed this work could be an opportunity to inform those who didn't know and to remind those who've forgotten... As a Korean, I cannot fully express the gravity of this history, but I focused on effectively portraying the people living in this era," he said.

"I need to understand the script in order to play a character. So I researched things about that history that I didn't know or had forgotten. Seeing that era in images shocked me a lot. There were a lot of situations that weighed heavily on my heart in various ways," the actor added.

The serie "Gyeongseong Creature" is set in 1945 in Gyeongseong during Japan's colonial rule (1910-1945). Courtesy of Netflix

Similarly, Han, who conducted thorough research, expressed regret over viewing images, especially those depicting the harrowing real-life chemical and biological experiments conducted by the imperial Japanese army in the 1930s and '40s.

"I looked into actual experiments that took place to immerse myself in the era. Many of them were related to women and testing their maternal instincts in the face of death, which were truly horrifying and shocking. To be honest, I wished that I hadn't looked them up," she said, adding that she tried to detach herself from her emotions to effectively portray the character Yoon.

"I felt I shouldn't bring these emotions into my acting. Yoon is a sleuth, searching for her mother, not an independence fighter... She's accustomed to Japanese oppression and feels powerless. So, I tried to avoid letting those emotions influence the character," she explained.

Park hinted that the second season of the series, set to be released later this year, will feature a much faster development of its storyline.

"I've seen reviews about Season 1's pace, but the second season is definitely much faster-paced and has unexpected elements," he said. "The story needed to have a solid build-up with Season 1 to let viewers enjoy the different aspects of Season 2. I feel people might re-watch Season 1 when Season 2 is released."