2556

September

 * September 25: A musical event, Believe, takes place at the UNSC Symphony Hall, and performed by the UNSC's own Symphony Orchestra. It is centered on remembering Master Chief Petty Officer John-117 and his service to the UNSC.

November

 * After November 7: Onboard the , Cortana, showing clear signs of Rampancy, files a report on the history of the Forerunners and Humanity.