Chief Kim Sung-Ryong
Kim Sung-ryong used to be a small time accountant from Gunsan who worked for the mob and cooked books. His life changes when he joins TQ Group as the new Chief of the Business Operations Department.
- Adorkable: He's cheerful and eccentric and over time, the Business Operations team comes to adore him.
- The Protagonist: Most of the show is centered around Sung-ryong and how he goes from a crooked accountant to a good man.
- Crouching Moron, Hidden Badass: Sung-ryong seems cheerful and ineffective but he's actually very intelligent, quick-witted and is also known be an extremely proficient accountant.
- Street Smart: Sung-ryong is capable of improvising on the fly, seeing through people's motives and knows how to use his surroundings to his advantage.
- True Companions: With the rest of the Business Operations team. At first, nobody likes him but they slowly warm up to him over time.
- The Tease: Sung-ryong loves blowing kisses to and winking at Yul, much to Yul's discomfort.
The Assistant Manager of the Business Operations team. Ha-Kyung is a strongly principled woman is not afraid of meeting challenges head-on.
- Beauty = Goodness: Ha-Kyung is a beautiful woman who is firmly on the side of good as well.
- Beware the Nice Ones: Ha-Kyung's temper is well-known to the Business Operations team, who even call her the real psycho of TQ.
- Nice Girl: She's a kind and intelligent woman who genuinely cares for other people and does not hesitate to offer help when she sees people in distress.
- Number Two: In the absence of Chief Lee, and even when Chief Kim is present, the rest of the Business Operations team considers Ha-Kyung to be a leader and mentor.
- Passionate Sports Girl: Ha-Kyung often goes to the batting cages to relive stress and is shown to be quite good at softball.
- Plucky Girl: Ha-Kyung thinks nothing of running into a mob of security thugs to rescue Sung-ryong.
Seo Yul used to be an ace prosecutor until the chairman of the TQ group appointed him to be the Director for Finance
- Ambiguously Evil: Chairman Park hired Yul to clean up TQ Group's messes.
- Broken Ace: Seo Yul is smart, good-looking, is a high-powered executive who commands respect. However, he does not believe in the power of good and finds it impossible to trust anyone, or even form relationships.
- Deuteragonist: A fair amount of story time is also devoted to Yul's growth from a disillusioned prosecutor to a ruthless executive.
- Even Evil Has Standards: Seo Yul is ruthless and cold but even he does not approve of brute force and nor does he approve of murder.
- Jerk with a Heart of Gold: Yul is a jerk to Sung-ryong most of the time. However he's the one who rescues Sung-ryong from being murdered by Chairman Park's thugs.
- Intelligence Equals Isolation: Yul is known for his brilliance but his intellect has also ensured he has next to no friends and does not know how to deal with people.
- Psychotic Smirk: Yul sports an impressively creepy smile when he's threatening Executive Director Jo. She is understandably terrified.
- Tall, Dark, and Snarky: Yul is good-looking, intelligent, not very tolerant of stupidity and always ready with a smart comeback.
An intern of the Accounting department who is undercover as a spy in TQ Group.
- Just Friends: She is good friends with Kim Sung-Ryong and plays a big role in helping him uncover TQ Group's problems.
TQ Group Employees
The son of Chairman Park and CEO Jang. Initially, he is a spoilt brat who spends the company's money on luxuries and behaves like a bully to the Business Operations team.
- Break the Cutie: After he joins the Business Operations team, he learns how terrible his father really is. The realization hits him hard.
- Butt-Monkey: Once Myung-seok joins the Business Operations team, as the junior-most person, he gets bossed around a lot.
- The Dandy: Myung-seok is always attired in patterned suits and cares a lot about his appearance.
- HeelFace Turn: Once Myung Seok realises that his father is a terrible person, he suffers a crisis of conscience and begins helping the Business Operations team in their fight against him.
- Hidden Talents: He can apparently speak Tanzanian (technically Swahili) and is the person who contacts the African branch of TQ to get information. He can also imitate his father's voice really well.
The oldest member of the Business Operations team. He's constantly worried about losing his job and making enough money to support his family abroad.
- Team Dad: He is frequently supportive of the Business Operations team and buys them food and tries to keep their spirits up.