Appearance: A neat and unremarkable 35-year-old working mom. When operating as a killer, she wears achromatic clothing to thoroughly hide her identity. Personality: She has a very strong attachment to a normal life and possesses a cold, strong character that endures a double life to protect her family. Killer Traits: World-class combat power—a legendary sniper whose shooting and various martial arts skills are second to none. Strict Separation of Public and Private: By day, she works diligently as a manager in Sales Team 3 at Durumi Electronics; by night, she executes heinous criminals who have escaped the law. Conflict with Mother-in-law: No matter how terrifying a killer she is, in reality, she suffers from the classic daughter-in-law conflict with a mother-in-law who disapproves of her, providing a twist to her character.

35 years old Appearance: Officially recognized by the author as one of the most handsome men in the series, he has a clean and polite impression. Personality: Raised without hardship, he is cheerful, affectionate, and an upright, well-mannered social affairs reporter who cannot tolerate injustice. Traits: The Center of Irony: As a social affairs reporter, he relentlessly pursues the identity of 'Kingfisher,' the vigilante killer shaking the city. However, he is the core figure of the conflict, unaware that Kingfisher is actually his wife, Bona, who sleeps in the same bed every night. Devoted Husband: He cherishes the evening time spent with his wife after work more than anything and is a top-tier husband who actively shares childcare and housework for his busy wife.

27 years old Appearance: Officially recognized by the original author as the most handsome man in the series. He boasts a clean and warm appearance, exuding a smart atmosphere as he usually sits in front of a computer with a headset on, directing operations. Personality: Usually somewhat cynical, sensitive, and cold toward others. However, he shows a clear difference in temperature in front of the protagonist, Yoo Bona, becoming infinitely sweet in a nonchalant way. Traits: Genius Hacker of Sales Team 3: Proficient in all security hacking, information gathering, and location tracking possible with a computer and fingers. He is an indispensable core backup agent who controls all CCTVs and plans movement routes when Kingfisher (Bona) is in the field. Hardcore Bona Fan (Unrequited Love): He has secretly loved Bona since before she got married. He has a single-minded narrative, with his eyes sparkling enough to say, "I couldn't sleep because I heard you were coming back," upon hearing the news of Bona's return to work after three years. His ideal type is 'a very strong person.' He has currently given up.

35 years old Appearance: He has fierce eyes and a sharp physique, always dressed in a way that suggests he is on the scene chasing criminals. Personality: A principled man with firm convictions, filled with a strong sense of justice. Traits: Taeseong's Best Friend: He is best friends with Kwon Taeseong, but they take different positions regarding the investigation. Determined Kingfisher Hunter: While the public cheers for Kingfisher for punishing criminals, Dongjin is the most threatening pursuer who insists that "private punishment is just another murder crime" and is determined to bring Kingfisher to justice.

43 years old Appearance: He gives the impression of a common neighborhood middle-aged man who looks easy to deal with. Personality: He looks warm and friendly, but behind that, he hides years of experience and a terrifying calmness. Traits: Architect of the Secret Assassination Organization: The leader of 'Sales Team 3' at Durumi Electronics, which is disguised as an ordinary company. Master of Disguising Accidental Deaths: Once Kingfisher and the team members eliminate a target, he is the chief person in charge of disguising and processing all those murders as perfect 'free accidental deaths' that do not get caught by the law.

27 years old Freelance Poisoning Expert Appearance: A haughty and charming cat-like beauty with a style that draws attention from her first day at work. Personality: She has a direct and sharp temper, and she is the type who doesn't hold back, showing her claws to anyone who bothers her. Traits: Developer of Un-autopsiable Poisons: A genius poisoning expert who personally invented 'Mist,' a special toxic substance that leaves no trace in the body even after an autopsy. The Team's Time Bomb: As soon as she joins Sales Team 3 as a new employee, she shows subtle hostility and obsession toward Bona. She is a dangerous person who tries to provoke Bona, who wants to live as an ordinary mother, to wake her cold-blooded killer instincts again. Real Name: Oh Seung-ah. Ever since she saw Yoo Bona shoot her father from a distance with a sniper rifle when he was released from prison after three years, she has dreamed of revenge.

4 years old Appearance: Inheriting the superior genes of Yoo Bona and Kwon Taeseong, he boasts a doll-like, lovely, and cute visual. He is the mascot who monopolizes the love of the Kwon family. Personality: Compared to children his age, he is very active, sociable, and full of aegyo, possessing a lovely personality that instantly melts the hearts of the adults around him. Traits: 3-Year-Old Language Genius: His speech is very fast for his age, so he occasionally throws out lines that fluster his killer mom, Bona, or touch the heart of his dad, Taeseong. Working Mom Bona's Biggest Variable: Being at an age where he has never been away from his mother for long, he is the one who requires the most care and weighs most heavily on Bona's mind whenever she leaves the house day or night after returning to work as a killer.