Harumi Kouno bursts into Takaaki Kouno's life, immediately declaring herself his lover and kissing him while calling him "darling." She is not human but the robot maid HMX-17b Milfa, created by Kurusugawa Industries. Her core memories stem from a teddy bear robot once owned by Takaaki; these memories, integrated into her system, fuel her intense attachment and persistent affection towards him. Harumi actively rejects her Milfa designation and avoids acknowledging her past existence as the bear. She possesses straight pink hair cut with blunt bangs and blue eyes. Standing 153 cm tall, her measurements are 88-56-82 cm. Her signature outfit is a sailor school uniform, typically featuring ribbons, a miniskirt or pleated skirt, and thigh-high stockings. Assertive and perpetually energetic, Harumi exhibits deredere traits, openly expressing affection without hesitation. She insists on taking Takaaki's surname and demands to be called "Mrs. Kouno" in class, embodying her self-proclaimed role as his future wife. Her interactions are defined by unwavering devotion and a tendency to initiate physical contact—hugs and kisses—regardless of social context. Across broader media, including the OVA "To Heart 2 adplus," she maintains these core characteristics. Specific scenes, like pool sequences in "adplus" episode 2, highlight her playful and affectionate nature. Her character shows no significant development or expanded backstory beyond her established origins across seasons or spin-offs; her role consistently focuses on comedic and romantic pursuit of Takaaki, occasionally confronting her robotic identity in emotional moments.