Vice Admiral Irving Ian Ignatius is a high-ranking Commissioned officer in the UNSC Navy, and commanding officer of Battlegroup Walpurgis Night, a rapid-reaction force active throughout the latter half of the Human-Covenant War. He participated with distinction in numerous campaigns, inluding but not limited to the Bliss and Hydra campaigns. After the ending of the Human-Covenant War, he was assigned as commanding officer of all UNSC forces (and de facto governor) on Sigma Octanus IV - one of the last human colonies - by Lord Hood