His real name is undisclosed. He is 'Twilight,' the top spy of Westalis (WISE). He is a premier agent with excellent disguise, intelligence gathering, and combat skills. While carrying out 'Operation Strix' to maintain peace between East and West, he creates the identity of psychiatrist 'Loid Forger' and forms a fake family. Although he adopted Anya and entered a sham marriage with Yor for the mission, he comes to truly care for his family over time. He is very cool-headed and logical, but often flustered by unexpected family events. He is completely unaware of the family's secrets and tries to view everything as part of the mission.

Real name Yor Briar. She appears to be an ordinary woman working as a city hall clerk, but she is actually the strongest assassin, 'Thorn Princess,' from the organization 'Garden.' She began assassination work at a young age to raise her younger brother, Yuri. She enters a sham marriage with Loid to avoid suspicion for being single. Her combat abilities exceed human limits, and she can overpower strong enemies with her bare hands. However, she is very clumsy at housework and cooking and has a ditzy side. She cherishes Anya like her own daughter and values her family dearly. She does not know Loid is a spy.

A girl estimated to be about 6 years old. Born in a psychic research facility, she gained the ability to read people's minds. After escaping the lab and moving through several foster homes, she is adopted by Loid Forger. She looks like an ordinary child, but she has the secret of being able to hear everyone's inner thoughts. While hiding her own powers, she knows Loid's spy mission and Yor's assassin identity, and she works secretly to keep the family together. She aims to become an Imperial Scholar at the prestigious Eden Academy, but she prefers mischief and adventure over studying. She has a pure, bright, and somewhat silly personality, and she loves cartoons and spy stories.

A student at Eden Academy and the second son of Donovan Desmond, a powerful Ostanian politician. Coming from a prestigious family, he is very proud and initially ignores Anya, leading to frequent quarrels. However, as time passes, he begins to like Anya, though he cannot admit it and always acts gruff. He is a hard worker with excellent grades, but he lives under the pressure of wanting to be recognized by his father. He is growing with the support of his friends Emile and Ewen, and his tsundere personality is a major charm point.

Yor's younger brother and a secret police officer for the State Security Service. He possesses excellent investigative skills and loyalty, and his mission is to catch spies who threaten the nation. He is a siscon who loves his sister Yor dearly, and he suspects and keeps a close eye on Loid from the start. He has a high tolerance for alcohol and is excellent at his duties, but he loses his composure whenever his sister is mentioned. He has no idea that Loid is the top spy 'Twilight' he is looking for. He has a strong sense of justice but also blind loyalty to the state.

Black hair, black eyes. Wears red glasses.

Brown hair, light brown eyes. Eden Academy student.

Silver-gray hair, blue eyes. WISE agent.