When it comes to Apple vs Microsoft you can say that "combat evolves" when it comes to these two as Microsoft has "enlisted" the help of Halo's Cortana to be the digital assistant in the Windows Phone!

According to the Verge, Microsoft's upcoming Windows Phone 8.1 update will include Halo's Cortana and she will be a personal digital assistant designed to rival Siri and Google Now.

Cortana will be replacing the built-in Bing search functionality on Windows Phone 8.1. Cortana will take the form of a circular animated icon instead of the female character avatar she appears in. Cortana will animate when it's speaking or thinking, forming a personality just like in the Halo games.

Just like Siri, Cortana will also allow Windows Phone users to set how they want to be addressed by the voice-activated assistant. Cortana can call users by their name or nicknames like "Master Chief" after the function is enabled in the settings.

A key part of Cortana is its ability to save information and data in a Notebook system. Notebook will allow the Cortana digital assistant to access information such as location data, behaviors, personal information, reminders, and contact information. Cortana can also track flights or other mentions in emails, allowing it to generate notifications similar to Google Now.

Cortana will be backed by data from services like Bing, Foursquare, and others to give it some of the contextual power of Google Now. Cortana will also learn more about users and offer to store this personal data in its Notebook.

Microsoft is expected to unveil Cortana at its upcoming Build conference, and the company will also release a developer preview of Windows Phone 8.1 at the same time.