Alpha is the main character of the series. As an A7-M2 model robot, one of the few production prototypes, she is one of the first of the A7 series and was named "Alpha." She has an unusual affinity with machines and people.

Unlike most characters with cheerful personalities, Alpha is sweet without being saccharine. Her pleasant disposition has won her several friends and loyal customers yet she is also capable of making deep insights and displays an unusual level of maturity during her more private moments. As the story progresses, she interacts more with her surroundings and the people around her, gaining more knowledge about life with her experiences.