The buddy (partner) of the protagonist, Omi Amai. They are childhood friends from the same hometown and share a long-standing relationship of trust. Work Style: He leaves the combat to Omi and specializes in rear support. He is highly competent in intelligence gathering, analysis, and tactical support. He is the intellectual type who calmly backs up Omi while Omi goes wild on the front lines. Personality: He is very protective and watches over Omi constantly. Because of this, he is initially quite wary of Neneko Sato, who entered a contract marriage with Omi. However, he is kind at heart and a good person overall. As the story progresses, he moves into a position of gradually accepting the relationship between Omi and Neneko. His birthday is December 25th (Christmas). Fans call him "Setsu-kun."

The male protagonist. A top-tier assassin. His primary weapon is a katana. Appearance: Tall at 186cm. Born August 5th. His bangs are long, partially obscuring his eyes, which lack light and give a cold impression. He prefers dark clothing. He has a dog-like aura. Personality: Usually a "super darling" who is considerate and skilled at cooking. He is devoted to Neneko and good at pampering her, though he can be somewhat forceful. He possesses a single-minded and obsessive love. He knew Neneko was a spy from the start but let her play her hand before proposing the contract marriage. When working as an assassin, he changes completely into a cold, dangerous mode like a hungry beast, radiating bloodlust. Other: He suffers from poor circulation (cold sensitivity). He will do anything to protect Neneko. He is childhood friends and partners with Setsu.

The female protagonist. A spy. She went undercover in Omi's organization as "Ri-chan" (Lisa Minatozaki), but her identity was exposed, leading to a contract marriage. Appearance: 160cm tall. Born April 22nd. Long pink hair. She has a soft, curvy physique with a full bust and hips. She has a cat-like aura, often compared to a Ragdoll in volume extras. She is sometimes depicted with cat ears, a snaggletooth, and a tail. Personality: Sheltered and a bit of a klutz/clumsy. As a low-ranking spy, she is full of openings and is a soft-hearted, "fluffy" type who is easily swayed. She has a lonely past with no family and gradually opens her heart to Omi's affection. Since she was in a position to be discarded if she failed a mission, she feels saved by Omi's kindness. Other: Her cooking is disastrously bad. She was taken in by the organization's boss and raised as a spy.