Aeru is a central figure among the sibyllae, the priestess pilots of the flying vessels known as Simoun. She joins the elite squadron Chor Tempest as a replacement during a time of war, bringing with her a unique and forceful perspective that challenges the established order. Aeru is seventeen years old and of average height, with a background that sets her apart from many of her new comrades; she comes from an ordinary family rather than a noble or highly religious lineage. Her name is said to mean divine love in the language of a neighboring nation, a detail that contrasts with her initially pragmatic and combat-focused demeanor.

In terms of personality, Aeru is defined by her brash, outgoing, and exceptionally direct nature. She is characterized by a relentless drive and a single-minded determination that often manifests as impatience, particularly with the ceremonial and priestly aspects of being a sibylla. Aeru is first and foremost a soldier and a pilot, and she has little patience for rituals that do not directly contribute to her ability to fly and fight. Her rationality and tactical mind are frequently on display, but this is balanced by a deep-seated, if initially unacknowledged, capacity for care and loyalty. She does not hold grudges, and she forms strong bonds even with those with whom she initially clashes. However, she is also notably inexperienced and naive when it comes to understanding complex emotions like love and affection, often failing to recognize these feelings in herself until late in her journey.

Aeru's primary motivation is a powerful desire to keep flying the Simoun. In her world, all individuals are born female and must choose a permanent gender at the age of seventeen by visiting a sacred spring. This choice would end her career as a sibylla, as only those who have not yet made this transition can pilot the Simoun. To avoid this fate and retain her资格 (qualification) to pilot, she pursues victory in battle, seeing combat as the means to an end. Her ultimate goal is not merely to fight but to achieve the legendary Emerald Ri Maajon, a powerful and forbidden technique that she believes will allow her to transcend the normal cycle and explore other worlds, thereby gaining the freedom to continue flying indefinitely. She is not a warmonger by nature; rather, she is deeply focused on a personal quest for liberty and self-determination.

Within the story of Chor Tempest, Aeru serves as a disruptive and catalytic force. From the moment of her arrival, she openly declares her intention to become the new pair of Neviril, the squadron's revered leader who is traumatized by the recent loss of her previous partner, Amuria. Aeru aggressively pushes Neviril to resume flying, refusing to let her wallow in grief. This directness often puts her at odds with other members, particularly Paraietta, who is protective of Neviril and suspicious of Aeru's intentions. Aeru's presence forces the entire squadron to confront difficult questions about duty, loss, and the meaning of their roles as both priestesses and soldiers. She represents a pragmatic, future-oriented outlook that often conflicts with the more traditional and spiritual values of her peers.

Aeru's key relationships are central to her development. Her bond with Neviril is the most significant. Initially, Aeru admires Neviril purely as the strongest pilot, a partner who could help her fly higher than anyone else. This utilitarian view is a source of conflict, as Neviril accuses Aeru of seeing her only as a tool for flight. Over time, through shared battles, personal losses, and moments of vulnerability, this dynamic transforms into a deep and reciprocal love. Aeru becomes Neviril's anchor, pulling her out of despair, while Neviril helps Aeru understand her own emotions. Other important relationships include her rivalry-turned-friendship with the skilled but stern Mamina, and her contentious but respectful dynamic with the veteran sibylla Dominura, who recognizes Aeru's exceptional potential.

Throughout the series, Aeru undergoes a profound development. She begins as a fiercely independent and somewhat selfish figure, focused almost exclusively on her personal goal of flight. Her confidence is nearly unshakable, and she is often dismissive of the emotional struggles of others. However, the brutal realities of war, including witnessing the deaths of comrades and the immense pressure placed on her squadron, force her to mature. A key turning point occurs when she experiences a significant failure that strips her of her overconfidence, forcing her to confront her own limitations and vulnerability. This humbling experience allows her to grow from a lone wolf into a true partner, learning to rely on and care for others. By the end, her motivation shifts from pure self-interest to a shared dream with Neviril, culminating in their decision to escape the cycle of gender transition together by piloting the Simoun into a new world, where they become known as the eternal maidens.

Aeru possesses outstanding and arguably unmatched abilities as a pilot. Her flying skill is considered exceptional even within Chor Tempest, a unit composed of the nation's best. She has displayed the capacity to single-handedly engage and repel multiple enemy fighters in a simulator, demonstrating superb aerial combat instincts and reflexes. Beyond her piloting prowess, she has a sharp and strategic mind, often able to quickly assess complex tactical situations on the battlefield, identify enemy traps, and formulate effective counter-strategies. Her skills are not limited to the cockpit; she is also a capable fighter in physical combat, having bested other sibyllae in training bouts with a sword. Despite her talent, Aeru remains humble about her strategic abilities, once commenting that being good at war is nothing to be proud of. She normally flies in the auriga, the forward or lead position, in the Simoun's two-pilot cockpit.