Since its debut 14 years ago on the original Xbox, Master Chief has saved the world numerous times and the Halo series has sold over 65 million units.

Microsoft has announced that the sci-fi first-person shooter series Halo has sold over 65 million games. The Halo franchise debuted back in 2001 on the original Xbox system with Halo: Combat Evolved. After spawning three sequels, one prequel and a variety of spin-offs, the franchise's combined sales have shown some significant progress over the years. Back in Oct. 2014, the Halo franchise' game sales were only at 60 million total. The bulk of this 5 million growth is likely from Halo: The Master Chief Collection, an anthology of Halo 1-4 for the Xbox One that launched in Nov. 2014, which featured an optimized version of Halo 2 using current-gen tech.

In 2000, Microsoft acquired Bungie Studios in order for them to work on games for its first game console. Following the launch of Halo 3 in 2008, the series' creators and longtime developers at Bungie decided to part ways with the company. They left the rights to the franchise with Microsoft and ended their business with them on amicable terms so Bungie could act as its own independent studio. Since then, Microsoft created its own in-house development team, called 343 Industries, which is dedicated to the Halo franchise. Since parting with Microsoft, Bungie went on to launch Destiny, which was met with overwhelming sales but lukewarm reviews.

Halo 5: Guardians is set to launch on Oct. 27 as an Xbox One exclusive.

100 Video Game Facts You May Not Know