John 117 is the main protagonist of the Halo series. He is a Spartan II, with MK VI Armor.
John 117 is a buff and heavyset (Spartan Armor weight wise) Spartan who is able to use any weapon. He is the ultimate Spartan, given his AI companion Cortana. However, Cortana sacrifices herself to save Master Chief, as he goes through a seemingly emotional breakdown in the video series Hunt the Truth. It has been revealed in Halo 5 that Cortana was still alive, but corrupted with power. She had taken over known UNSC, Swords of Sanghelios, and Covenant territory.
The modern day Cortana phone voice may be modeled off of Cortana from Halo.