Nexuiz was originally developed by Lee Vermeulen and Forest 'LordHavoc' Hale, who started Alientrap Software in the summer of 2002. The goal of the project was to create a high quality first person shooter that could be played freely across all platforms in one package: PC, Mac, and Linux. The engine that powered Nexuiz was Forest Hale's Darkplaces engine.

The first version of the game was released in 2005. Development continued with many online contributors over the years, with version 2.5 released in October of 2009. Since its release it has been downloaded over 5 million times, and is included with many Linux distributions.

For centuries the Kavussari and Forsellians have waged a galactic war. Over time the two races entered into treaties with the Herald Accord, a union between different cultures in the galaxy. Even though peace settled across their planets, the seething hatred between the races kept the fire of war simmering under the fragile truce. Sensing their newest members could spread war throughout the galaxy; the nations in the Herald Accord gave the Kavussari and Forsellians a choice. Pit their warriors against each other in the arena rather than on the fields of war, or face total annihilation. The Nexuiz was formed, a series of battle arenas on the home planets of the Kavussari, Forsellian and the ruined planet of Atavirta.