Fujiwara no Akiko is a supporting character in the Heian-era story. She is a princess of the Fujiwara clan, which places her in a high station within the Imperial Palace, and her noble status comes with strict customs and expectations that she often finds frustrating. Her life changes dramatically when she encounters Abe no Masahiro, the young onmyouji who saves her from a demon attack, an event that marks the beginning of their deep and lasting friendship.

Akiko possesses a gentle and kind nature that endears her to nearly everyone she meets, including the powerful Twelve Shinsho, the shikigami who serve Masahiro's family. Despite her royal upbringing, she is remarkably strong-willed and independent, frequently growing annoyed with the restrictive traditions her status demands. She much prefers to do ordinary tasks like shopping and cooking for herself rather than relying on servants, a trait that is encouraged and supported by Masahiro's mother. Her personality is also marked by a sense of guilt; she often worries about being a burden or causing trouble for others, and she makes a conscious effort to help those around her in any way she can, even knowing she is not physically powerful.

Her primary motivation is closely tied to Masahiro. She admires his strength of will and, as the story progresses, develops romantic feelings for him. She is determined not to be a passive figure in his life, instead choosing to be an active source of support. Her role in the narrative is significantly defined by a unique and powerful spiritual gift. Akiko is one of the few people of her time to possess the Kenki ability, which allows her to see demons and spirits. In fact, her talent for seeing supernatural beings is said to surpass even that of the legendary onmyouji Abe no Seimei and his grandson Masahiro, and she can also sense the location of the Twelve Shinsho even when they are in a calm state. However, this rare and potent spiritual power makes her a constant target for malevolent demons who seek to exploit her energy, placing her in frequent danger and making her a key figure in many conflicts. This has led to her being characterized as a damsel in distress who requires protection, though her own efforts to avoid being a burden complicate this label.

Her most significant relationship is with Masahiro. What begins as friendship after he rescues her deepens into a mutual romantic attachment, and he makes a solemn promise to protect her from the demons that covet her power. She eventually comes to live in Masahiro's home, further solidifying her place in his life. She is also well-liked by the Twelve Shinsho, including Guren, Rikugo, and Genbu, who admire her spiritual sight and gentle character. She describes Tazugimi, another character she encounters, as a little rowdy but fundamentally a good kid. Over the course of the story, Akiko develops from a princess who is initially a target for demons into a more proactive and independent young woman who learns to navigate daily life outside the palace walls and actively supports Masahiro, all while grappling with the dangers and responsibilities that come with her extraordinary spiritual abilities.