Nemu Hiiragi is one of the three leaders of the Wings of Magius, an organization of magical girls in Kamihama City, and a central figure in the first story arc of Magia Record. She was originally a sickly girl who spent much of her childhood in the hospital, where she became close friends with Ui Tamaki and Touka Satomi. During this time, she developed a deep love for reading and later began writing her own stories as a way to seek approval and connection. Her writing eventually gained recognition online, earning her a reputation as a literary prodigy.

Nemu possesses a calm, humble, and soft-spoken personality that contrasts with Touka's more assertive and analytical demeanor. Despite her gentle exterior, she is highly intelligent and often acts as a grounding influence on Touka, questioning her more extreme conclusions and encouraging objective consideration of situations. This tendency to argue from an opposing viewpoint has been likened to playing the devil's advocate. Nemu is introspective and prone to quiet internal conflict; she grapples with feelings of emptiness and doubt about the cost of the Magius' mission, even as she remains committed to its goal of saving magical girls from becoming witches.

Her motivations are rooted in a longing for closeness and love, stemming from the emotional distance she felt from her family during her long hospital stays. While her parents cared for her and her brother was affectionate, the time apart left her feeling that material gifts and distant praise were not substitutes for genuine intimacy. This desire to be loved and to bring people together shaped her vision for the Magius' base, which she conceived not as separate facilities but as a welcoming, hotel-like space called Fendt Hope, where everyone could gather together. She equated expanding the base with writing a sequel, using her storytelling as a way to connect people over time.

As one of the three Magius, Nemu serves as the creator of the rumors, or uwasa, that the organization uses to gather energy and influence. Her magical ability allows her to weave stories into tangible realities, literally wrapping the world in her narratives. Her ultimate dream is to create a world without witches, a goal she and the other Magius pursue through the doppel system, which aims to prevent magical girls from succumbing to despair. However, this ambition carries a heavy personal toll; her powers drain her significantly, leaving her exhausted and requiring long recovery periods.

Nemu's most significant relationships are with Touka Satomi and Ui Tamaki. She and Touka often clash intellectually, but they also share a deep mutual respect, with Touka acknowledging that Nemu is better at calmly considering situations. Together with Alina Gray, the three Magius drive the organization's plan. Nemu also followed Iroha Tamaki during the early days and knew the truth about Ui's wish and transformation into a magical girl. This connection becomes a source of profound regret, as Nemu later acknowledges that she ended up hurting the very person she wanted to save.

Throughout the story, Nemu undergoes significant development as she confronts the ethical cost of the Magius' methods. She initially experiences an unfocused emptiness, which she rationalizes as the result of a world that fails to recognize its magical girl saviors. But after witnessing the death of a White Feather, she begins to question whether the salvation she offers is genuine or merely a comforting story. In the aftermath of the conflict, she accepts responsibility for her sins, recognizes that she caused harm to someone precious to her, and expresses a clear desire for atonement. Despite the scale of her ambitions, her most personal wish remains a simple one: to be told that she is loved.