You can only carry two guns at a time there is no Hyperspace Arsenal to speak of (although in the first two games, the weapon you didn't have equipped was invisible to other players).

The core of Halo gameplay revolves around the wrinkles it presents in the First-Person Shooter formula. sidekick, battle the Covenant and discover the 'Halos': massive Forerunner Ring Worlds hiding immense power.

Over the course of the series, he and Cortana, his A.I. The Spartans, clad in Powered Armor and led by Master Chief Petty Officer John-117, are unmatched as warriors, but even they are not invincible, and by the start of the first game the Chief is The Last of His Kind. While the United Nations Space Command is vastly outmatched by the Covenant's superior numbers and Forerunner-based technology, mankind has one advantage: the SPARTAN-II Super Soldier program. In the 26th century, Earth and its colonies are at war with an alien theocracy known as the Covenant, whose leaders have declared humanity an affront to their gods. It has since blossomed into multiple sequels, Gaiden Games, and a substantial Expanded Universe. Halo is a Space Opera and Military Science Fiction franchise that began life as an Xbox exclusive First-Person Shooter created by Bungie Studios and published by Xbox Game Studios.

If you were looking for the trope, see Holy Halo.

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