Kwak Jung Hwan

Kim Je Ha, a former mercenary known as “K2,” becomes a fugitive after being wrongfully accused of killing his girlfriend in Iraq. He returns to Korea and works as a bodyguard for Choi Yoo Jin, the wife of presidential candidate Jang Se Joon. Je Ha plans revenge on Park Kwan Soo, Se Joon's rival, whom he believes ordered his girlfriend's murder. While guarding Go An Na, Se Joon's reclusive daughter, Je Ha and An Na grow close. However, Je Ha's loyalty is tested when he learns that Yoo Jin, his boss and ally in revenge, is the one threatening An Na. (Source: MyDramaList)

Kang Bok Gu, a tough K-1 fighter with a tragic past, falls in love with Cha Eun Seok, a TV talent and actress. His love is forbidden because of a misunderstanding that led to his emotionally wounded brother’s accident. Fueled by hatred and revenge, Bok Gu becomes Eun Seok's private bodyguard, determined to destroy her. However, as he carries out his plan, his feelings for her grow deeper, complicating his desire for vengeance. Bok Gu, a cold and detached man, has long used martial arts as an escape from past heartbreak. (Source: MyDramaList)

Baek Shi-Yoon is an ex-secret agent and a well-trained human weapon. Hiding his past, he buys the bar "Neighborhood" and runs it is as the owner. He gets close to the neighborhood regulars at his bar and sympathizes with their pain. Shi-Yoon then meets a young man who works as a temporary employee, but who wants to become a police officer. Shi-Yoon trains him as a secret agent and they fight together against evil.