Mao Nonosaka is a fourteen-year-old middle school student who appears as a supporting character in The Future Diary. She is one of Yukiteru Amano’s classmates at his new school and quickly becomes part of a close group that includes Hinata Hino, Aru Akise, and Ouji Kousaka. Mao has long light purple hair and aqua blue eyes, and she is often seen carrying a camera, which she uses to photograph her surroundings—especially Hinata. Her personality is outwardly gentle, polite, and perky, and she habitually uses honorifics when addressing others. Beneath this friendly exterior, however, Mao harbors an intense romantic obsession with her best friend Hinata Hino. She is openly lesbian and deeply proud of her affection, willing to do anything to protect and please Hinata. This devotion drives most of her actions throughout the story. While Mao does not possess any notable combat abilities, she is smart and resourceful, using her photography skills to gather information. She later becomes the sub-owner of a special diary known as the Lovey-Dovey Hinata Diary, which records Hinata’s activities and growth. Mao’s role in the narrative shifts from a seemingly ordinary friend to a more antagonistic figure when her loyalty to Hinata leads her to threaten Yukiteru with a knife and to act as a willing accomplice in Hinata’s scheme to harm Aru Akise. Her key relationships are defined by her singular focus on Hinata; she is close to Ouji Kousaka and initially friendly with Yukiteru and Aru, but her protective obsession overrides those bonds. Mao experiences little long-term development, as her character arc primarily reveals the darker consequences of her unwavering devotion, culminating in a brief but violent confrontation that underscores the lengths she will go to for the person she loves.