049 Abject Testament is a Forerunner monitor created to maintain Halo Installation 03 (Gamma Halo).
The Didact was a once revered ancient Forerunner commander who battled the Flood during their civilization’s fatal war with the parasite.
343 Guilty Spark is a Forerunner monitor created during the final days of the Flood War in order to maintain Halo Installation 04 (Alpha Halo).
The Librarian was responsible for the Conservation Measure, an effort to ensure the survival of sentient species from the destruction effects of Halo.
One of the most powerful Forerunner AI ever made, Mendicant Bias was turned against his creators by Gravemind.
The Master Builder was one of the most powerful Forerunners to have ever lived, and was responsible for designing and commissioning the Halo Array.