Observer Alpha

The main Siren figure seen throughout the story, as her name implies her purpose is to observe the growth of humanity (or to be specific, the growth of the ship girls belonging to humanity) and report the data to the "Creator". As an observer, she interacts with the protagonists sparingly. Alpha spends most of her time working behind the scenes to collect data, sending them to both the Creator and Tester Beta so the parameters of the next simulations could be better adjusted