Numerous K-drama stars demonstrate their exceptional acting prowess and versatility by skillfully embodying both “green flag" and "red flag" characters. A "green flag" character is one who exhibits positive traits such as kindness, reliability, and emotional intelligence. Conversely, a "red flag" character often displays negative traits like manipulation, deceit, or a volatile temperament.

Here are five popular K-actors who have captivated audiences with both green-flag and red-flag roles.

Byeon Woo Seok [Lovely Runner and Strong Girl Nam-soon]

K-drama fans have dubbed Byeon Woo Seok the "Greenest Forest" for his portrayal of Ryu Sun-jae, who is deeply in love with Im Sol, in "Lovely Runner." In contrast, he also played the red flag antagonist Ryu Shi-oh, a drug lord, in "Strong Girl Nam-soon."

Choi Woo Shik [Our Beloved Summer and Fight For My Way]

Choi Woo-shik, as Choi Woong in “Our Beloved Summer,” is the epitome of a green flag and embodies the ideal boyfriend. But Woo-shik in “Fight for My Way" is sure to leave you frustrated as Park Moo-bin, with his red flag behaviors, who tried to win Ae-ra despite being engaged.

Song Kang [My Demon and Nevertheless]

Crazy for his love Do Do-hee, Jeong Gu-won, a 200-year-old demon from “My Demon” portrayed by Song Kang, shows how he’s a green flag despite not being a human. However, Song Kang as Park Jae-eon in “Nevertheless” is the flag bearer of red flag characters in the K-drama world.

Ok Taecyeon [Dream High and VINCENZO]

Ok Taecyeon in “Dream High” as Jin-guk is a green flag, characterized by his supportive nature, loyalty, resilience, moral integrity, empathy, personal growth, and dedication. Conversely, his role as the infamous crime lord Jang Jun-woo, aka Jang Han-seok, in “Vincenzo” is that of a crazy psycho red flag villain.

Im Siwan [Summer Strike and UNLOCKED]

Ahn Dae-bom, an introverted math genius from “Summer Strike,” beautifully portrayed by Im Siwan, is a standout green flag male lead. Siwan further demonstrates his versatility in the movie “Unlocked” as Oh Joon-yeong, a psychopath and cybercriminal.

Which K-actor leaves the strongest impression in both green flag and red flag roles?