Technically, Cortana isn’t supposed to exist for at least another 500 years, but that’s not stopping Microsoft from bringing her to life this week. While Apple has Siri and Google has Google Now — both digital assistants that run on smartphones — Microsoft is taking an approach that mixes the best of the competition with its own unique take. Based on a 26th-century artificially intelligent character in the Halo video game series, Cortana will debut as part of Windows Phone 8.1, the next big update for Microsoft’s mobile operating system.

By learning your habits and interests continuously, Cortana is positioned as a personal digital assistant that helps you organize your day-to-day activities, alongside regular web searches for information. Cortana will act as the primary way to discover and search for information on Windows Phone 8.1, or just an assistant to manage your meetings, reminders, and daily life. She’s smart and witty, all while being designed to closely resemble a human assistant. With the competition already years ahead, Cortana arrives at a time when Microsoft is focused on catching up in mobile. Cortana is a significant new feature for Windows Phone 8.1, one that has been in development for more than two years. In many ways, Microsoft’s bold new mobile efforts rest on her virtual shoulders. This is the story of Cortana, and how she came to be.