A2 is one of the protagonists of NieR:Automata. She is a prototype of the YoRHa android line. Combat data from her and her comrades were used to create the superior current lines, including 2B and 9S. She doesn't like to speak and often keeps to herself. She was part of the first YoRHa squadron deployed to Earth as part of the Pearl Harbor Descent during the early years of the 14th Machine War. After the war, she found peace and opened up, becoming sociable and playful, flirtatious even.