Ryoo Seung-wan, an established filmmaker in Korea known for bringing witty, high-adrenaline action to the big screen, has returned with “I, the Executioner,” a sequel to the 2015 mega-hit cop movie “Veteran.”

The first film in the series follows veteran detective Seo Do-cheol (Hwang Jung-min) as he takes down corrupt chaebol heir Jo Tae-oh (Yoo Ah-in). “I, the Executioner” – known as “Veteran 2” here -- follows Do-Cheol, as he teams up with rookie cop Park Sun-woo (Jung Hae-in) to track down a serial killer who taunts the police by announcing his next victim before committing each crime.

“I, the Executioner” distances itself from the 2015 film by portraying darker, down-to-earth topics and timely social issues that make not only Do-cheol but also the audience think.

As they try to attract viewers, YouTubers create confusion for the police as they spread rumors about whom they think the serial killer -- whom the public dubs "Haechi" after the ancient Korean mythical animal -- is.

Although Haechi seems to kill only those he believes "deserve" punishment, such as those who have committed crimes, his real intention remains unknown throughout the movie. But his actions are so cruel that they can't be justified.

Director Ryoo explained that "Veteran" has a structure of good versus evil, but "I, the Executioner," is about what people think justice is, asking, “Is it right for someone to kill a criminal, as the public is being swayed by YouTubers and does not trust law enforcement?”

“To be honest, ‘Veteran’ started out not as a blockbuster movie. So I even became afraid after the movie became successful. Over the past nine years, I saw many different varieties of cop movies such as ‘The Roundup’ and ‘Extreme Job’ opening in the theater, giving me a sense of worry that I should not repeat the simple cop flick style that I did in the first installment,” Ryoo told reporters during an interview in Seoul on Sept. 11.

“But then I came to realize that as a director, pouring out all my anger against society into a movie and the audience being fascinated by that became uncomfortable. Also, I experienced that someone I criticized for being a perpetrator turned out to be a victim, giving me the thought that me defining what justice is can be dangerous,” Ryoo said.

He said he also wanted to portray the personal development of Do-cheol in the sequel.

“His son turns 19 years old in the sequel and becomes the target of school violence, an issue that Do-cheol cannot openly discuss at home or at work because he originally believed that kids grow up by fighting. But then later in the movie, he sincerely apologizes to his son (for having thought that way),” Ryoo said.

Hwang Jung-min said that playing Do-cheol, he was touched by how Do-cheol becomes responsible for his own actions and words.

“My son is also 18 years old now. I could immerse myself in Do-cheol as a father and husband. I’ve discussed a lot with the director about how Do-cheol becomes a responsible adult. I can say that this character was 100 percent made by myself,” Hwang told reporters in a separate interview in Seoul on Sept. 10.

“The sequel leaves the audience with the message that justice never dies. That is why the last scene, in which Do-cheol wants to keep the villain alive, is very important, because he wants him to get punished and brought to justice,” Hwang said.

Actor Jung Hae-in newly joined the franchise as Park Sun-woo, a rookie police officer with distorted passion and warped sense of justice.

Jung said he did extensive research into the character, as he wasn’t able to grasp this sociopathic character fully.

“I focused on portraying Sun-woo, who is held captive by his beliefs and value system. Not only was shooting physically tiring due to the action sequences, I also had some psychologically challenging moments because I had to understand why Sun-woo was that way and had done (what he did). But my solution was to act without having to find a clear answer,” Jung told reporters in a separate interview in Seoul on Sept. 11.

“There was no clue in the script, so I imagined myself what kind of life Sun-woo may have lived. But then the director said, I don’t need to improvise such stories to play Sun-woo. So I could rather focus on straightforward acting,” he added.

“I, the Executioner” hit local theaters on Friday.