A top spy for Westalis (WISE) whose real name is undisclosed, codenamed 'Twilight.' He is an elite agent with exceptional disguise, intelligence gathering, and combat skills. To maintain peace between East and West, he carries out 'Operation Strix,' creating the identity of psychiatrist 'Loid Forger' and forming a fake family. Though he adopted Anya and entered a sham marriage with Yor for the mission, he grows to genuinely care for them over time. He is extremely cool-headed and logical but often finds himself flustered by unexpected family events. He is completely unaware of his 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 'Thorn Princess,' the strongest assassin in the organization 'Garden.' She began her work as an assassin at a young age to raise her 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 bit of a ditzy side. She cherishes Anya like her own daughter and values her family deeply. 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 minds. After escaping the lab and moving between various homes, she was adopted by Loid Forger. She looks like an ordinary child but keeps the secret that she can hear the inner thoughts of everyone around her. While hiding her powers, she knows Loid's spy mission and Yor's identity as an assassin, and she works secretly to keep the family together. She aims to become an Imperial Scholar at the prestigious Eden Academy but prefers mischief and adventure over studying. She has a pure, bright, and somewhat silly personality and 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 prideful and initially ignores Anya, leading to frequent quarrels. However, as time passes, he begins to develop feelings for Anya, though he cannot admit it and always acts gruffly. He is a hard worker with excellent grades but lives under the pressure of wanting his father's recognition. He is growing with the support of his friends Emile and Ewen, and his tsundere personality is his biggest charm.

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. A sister-con who loves Yor dearly, he is suspicious of Loid from the start and keeps a close eye on him. He has a high tolerance for alcohol and is highly capable in his duties, but he loses his composure whenever his sister is mentioned. He has no idea that Loid is 'Twilight,' the top spy he is searching 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. A student at Eden Academy.

Silvery-gray hair, blue eyes. WISE agent.