Forerunners

The Forerunners are a fictional ancient, technologically advanced humanoid civilization in the Halo video game series and related media. They precede humanity in the series’ timeline and once governed a vast interstellar empire. Guided by the Mantle of Responsibility, they believed it was their duty to steward life across the galaxy and to guide younger species toward a place in the cosmic order.

Forerunner society was organized around monumental engineering projects and advanced artificial intelligence. They built extensive networks of installations, including the Halo rings, the Ark, and shield worlds, and deployed artificial intelligences to manage infrastructure and security. Notable Forerunner figures include the Librarian, who pursued biological stewardship and the propagation of life, and the Didact, a military leader who played a central role in later conflicts. Halo-era AI such as 343 Guilty Spark also feature prominently in their lore.

The Forerunners faced a catastrophic threat from the parasitic Flood. To halt the Flood’s spread, they deployed the Halo Array—ring-like superweapons that wipe out all sentient life in the galaxy, thereby starving the Flood of hosts and preserving life elsewhere. After a protracted struggle and political upheaval, the Forerunner civilization collapsed, leaving behind extensive ruins, ancient weapons, and vast artifacts that would influence later species, especially humans, who discover and repurpose their technology.

Legacy of the Forerunners continues to shape the Halo narrative through ruins, preserved technologies, and the lingering ethical questions of stewardship and contact with their artifacts.