The Forerunner Infestation Force was the bulk of the Forerunner Empire's forces dedicated to destroying Flood infestations while the army fought the flood on the front lines. It was one of the most sucessful sections of the military and recieved many honors and bonuses in equipment. However after the Battle of Iris, where many FIF members were living, around one quarter of the whole organisation was consumed by the flood. After that they failed to win many battles and the Infestation Force, along with around 95% of the Forerunner Species, was killled by the Halo Array. The last survivor of the Infestation Force was crushed by High Charity's landing on the Ark; although this did not mean the entire species was extinct.