Clara Kisenaria serves as a member of the First Unit of Dorothea, the government agency tasked with regulating illegal fairy activity in the aftermath of the Unification War. She is a young woman with long, straight brown hair that she typically wears down and a pair of glasses that complement her measured and intelligent demeanor. Like her colleagues, she usually wears the standard Dorothea uniform, which she carries with an air of professionalism.

Among her peers, Clara is defined by her serious, sensible, and meticulous nature. She is a straightforward individual who approaches her duties with a level of discipline and focus that can be intimidating to those around her. While she is not overtly emotional, her personality includes a sharp, almost sarcastic wit, which she occasionally displays in her interactions with others. Although she is dedicated to her work, she is not immune to personal frustrations, notably her dissatisfaction at being frequently partnered with Serge Tova due to the compatibility of their fairies, a pairing she openly dislikes. Despite this complaint, her interactions with Serge reveal a deeper layer of care, as she has shown visible concern for his safety during dangerous missions.

Clara's primary motivation for joining Dorothea is deeply personal and rooted in the recent war. She is an ordinary human who was saved by the Fairy Soldier Nein Auler during the conflict. This event left a profound impression on her, inspiring her to take a rare and significant step. Unlike many who are born with or forced into becoming Fairy Soldiers, Clara voluntarily underwent a fairy organ transplant to gain her powers, specifically so she could enlist in Dorothea and dedicate herself to the organization's cause. This choice highlights her strong sense of gratitude and her commitment to maintaining order in a world still recovering from chaos.

In the field, Clara is a capable combatant, proficient in both firearm use and swordsmanship. However, her true strength lies not in direct confrontation but in intelligence and reconnaissance, thanks to her contracted fairy, Tomereez. While Tomereez is physically small and considered too weak for direct combat, its unique ability to link with Clara's senses makes it an invaluable asset. She can deploy the fairy to discreetly scout areas, detect hidden enemies such as Fairy Soldiers, and even disorient opponents, causing them to miss their targets or injure themselves. Her strategic role in the First Unit often involves providing critical information and long-range support, as demonstrated when she helped Serge aim during a sniper operation. She is also a skilled investigator, capable of handling herself in dangerous situations, from dispatching thugs in a bar to participating in high-stakes missions to recover pages of the Black Fairy Tome.

Throughout the series, Clara forms key working relationships with several main characters. Her partnership with the new recruit Marlya Noel allows her to step into a mentor-like role, where her experience and level-headedness provide a steadying influence. During one of their missions, Clara opens up about her past and her reasons for joining Dorothea, explaining how Nein Auler saved her and how she has chosen to hold onto her memories of loss as something that makes her fortunate. This moment reveals her thoughtful philosophy on loss and memory. Her dynamic with Serge Tova evolves beyond simple irritation; while she is often annoyed by his flirtatious comments, her reactions to his injuries suggest a deeper, if unspoken, bond of trust and care between the two agents. Ultimately, Clara Kisenaria acts as a steady, reliable backbone for her unit, using her unique abilities and unwavering sense of duty to protect others, just as she was once protected.