Aisha Krishnam is a character of Indian origin, identifiable by the bindi she wears on her forehead and her dusky complexion. Her appearance is that of a seventeen-year-old girl, but due to a long period in suspended animation, her chronological age is thirty-one. She is the daughter of Dr. Krishnam, a scientist who conducted pioneering research into bio-nanotechnology. Born with an incurable illness, Aisha became the subject of her father's clinical experiments involving the fusion of the human body with nanomachines, a process known as human-machine integration. After a scandal regarding these experiments, her father went into hiding with her and eventually placed her into artificial hibernation before his death, entrusting her with the future. She was discovered years later, after the conclusion of a great war against an enemy known as the Worms.

Aisha is characterized by her extreme quietness and a demeanor that appears emotionless and indifferent to most things. This personality, which others initially perceive as cold or frightening, is a result of her unique circumstances and her lack of ordinary social experiences. Her understanding of the world is often practical and literal, viewing things like cameras as mere recording devices rather than tools for preserving memories. Despite this exterior, her motivations are driven by a deep sense of purpose inherited from her father. She willingly continues his work, dedicating herself to countering the threat of the Worms, whose origins are connected to her father's nanotechnology. She becomes the fifth pilot of a Sonic Diver, a mechanized combat unit, specifically piloting the Shunya Custom.

Her role in the story is initially that of a mysterious assistant to Dr. Kiriko Suou, but she is later revealed to be the original prototype for the Sonic Diver system. Aisha possesses a profound psychic ability to synchronize with and even remotely control Sonic Divers and the Worms themselves. This synchronization rate exceeds one hundred percent, but it comes at a great cost. Using her abilities severely depletes her physical strength, and piloting a Sonic Diver causes her to lose all memories of the time she is connected to the machine. She does not remember a simulated battle she participated in as a test pilot.

Aisha is initially feared and ostracized by the crew of the aircraft carrier Kouryu, as rumors label her the origin of the Worms. Otoha Sakurano is the first person to treat her with consistent kindness, forming a key relationship that helps bridge the gap between Aisha and others. Aisha also has a significant relationship with Dr. Kiriko Suou, under whom she works and who protects her. Her unique abilities and her connection to the Worms put her in direct confrontation with other characters, such as Elise von Dietrich, who hates the Worms, though they later come to an understanding after Elise learns the full truth of Aisha's past. Over time, her willingness to use her powers to protect the ship helps resolve the crew's misunderstandings.

Throughout the narrative, Aisha's development is subtle but significant. She moves from being a tool or a source of fear to a person who makes a conscious choice to sacrifice herself to end the conflict. In the final battle against the Worms' nest, she pilots her Sonic Diver to deliver a virus program. By using her powers to restore a human who had been transformed into a messenger for the Worms, she brings the conflict to an end but falls into a prolonged coma as a result. She remains unconscious for half a year after the war, regaining awareness only when the other Sky Girls take to the skies once more. Her most notable abilities include telepathically controlling Sonic Divers and Worms, which is an unconscious act she often performs, and having a physical body fused with nanomachines that serves as the foundational technology for both the Sonic Divers and the enemy Worms.