Akane Asamiya is Kirika Kusanagi and Yoriko Yagami's best friend and classmate who, like them, lived an ordinary life as all the other girls attending Kyoto High School in Japan before the incident that changed her life. One day the trio went on a field trip to the local genetics laboratory near Downtown Kyoto when a fight broke out nearby where the girls are touring between an industrial spy and an operative of British Intelligence MI6. The girls soon investigate the area, where the saboteur inadvertently crashed into a vast of Erlenmeyer flasks containing chemicals and mutated genetic bacteria. The mixed spillage created an after fume that filled the room where the girls are. The saboteur and the MI6 operative escaped, but the room suddenly sealed of and trapped the girls, forcing them to suffocate under the vile fumes, only two be saved a few seconds later by the area's ventilation system. After the incident, the girls physiology were slightly altered as the result of the fumes, giving them extra-sensory powers including a "mental warning" radar-like sense that warns them of danger. This led to a chain of events that forced Akane and her friends to join MI6's Tokyo branch as part of a task force dealing with the activities of the notorious international crime organization SABRE. Being the most athletic yet less talented of the trio, Akane tries her best to be a good team member, even if she occasionally screws up a mission with her aloofness and clumsiness.

        Akane is the trio's resident bubblehead and has less experience than Kirika and Yoriko when it comes to combat, and she is notorious for screwing up a mission due to her occasional clumsiness and not concentrating on the task in hand due to her constant daydreaming, especially in the middle of a mission. When push comes to shove however, and if she can concentrate more of her time in combat training then flirting, she can be a capable fighter. Akane, though possessing the beauty and looks of someone as popular as Kirika, she always has a knack of being rejected by boys who sees her as nothing more than an airhead, she searches for one who can see her for what she is in the inside, especially when she bumps in to an attractive foreign boy during a mission. Always friendly and polite to others and loyal to the other girls, Akane, despite having deep concerns of getting hurt herself, will risk everything to help out whenever she can, especially when her friends are in danger. Her favorite hobbies are being lead singer and guitarist of the local school band, wearing gothic clothing and maid uniforms on occasion, flirting with boys, though gets rejected except on missions, and collecting stuffed teddy bears. Her favorite food is any kind of hard candy.

         Like her friends Kirika and Yoriko, Akane possesses, as the result of the fateful lab accident, a sixth-sense "danger" radar, a psychic radar that warns hear of nearby danger or immanent physical harm. She also develop superhuman agility and reflexes from the accident. She is well-trained, even more so than the other girls, in a wide variety of sports including track and field, gymnastics, biking, and swimming. As a top agent in the MI6, she gains access to agency's prototype gadgets, weapons, vehicles and aircraft. Like her friends, Akane carries a secretly concealed utility belt containing such items such as smoke bombs, non-lethal shurikens, a microfilm camera, a miniature MP3 recorder, and an optional sleep dart wrist gun.