A2 is a combat-model whose purpose as a prototype was to speed along the production of the B and S models like 2B and 9S. Before the events of the game, she was part of a unit, who was employed to Earth in of the earlier Machine Wars. After suffering the loses of her beloved comrades, she went rogue in her own personal vendetta "to destroy every machine". It is as much a purpose she's set for herself to keep going, as it is a distraction for the desire to be with her comrades. While seemingly hostile to every machine, A2 lets her guard around Pascal once she realizes that she and her people are docile.
She's also not without sympathy, hesitating slightly as she takes 2B's life before the virus gets any worse on her, she expresses sadness and sympathy towards Pascal when he loses his mind over the loss of his Machine children and villagers.
- The prequel stage play mentions that A2's design was based on a little girl, who lived happily with her grandma. Combine that with her attitude, and Emil's behavior around her, it's very possible this girl was none other than Kainé.