TIME PERIOD: October 27th, 2558 - NOW
When Master Chief and Cortana battled the Ur-Didact over Earth in 2557, the rampant fragments of Cortana were thrown into slipspace and emerged at the Forerunner Domain. Gaining access to the most powerful source of knowledge known in the galaxy, Cortana used it to take control of the Forerunner Guardians buried beneath countless planets and moons. Her actions caused the death of thousands if not millions of humans, Sangheili, and many other former Covenant species. While it is not known whether there is someone or something else pulling the strings behind the scene, Cortana's stated goal is to remove all war, famine, and suffering by subjugating all species under her rule.