The Lord of Admirals, born Forthencho, was an ancient human military commander during the Human-Forerunner Wars, around 10,000 years prior to the Forerunner-Flood War and the firing of the Halo Array. At the close of the war, the Lord of Admirals, along with the few remaining ancient humans, surrendered to the Forerunners, eventually having their essences harvested into geas by the Librarian for later use.
Following the war, ancient humans were devolved into a more primitive state and set to repopulate Erde-Tyrene. As the Librarian looked over this process, she ensured that the harvested geas from ancient humans was implanted into these new humans. These geas would come out later once they were needed, with the Lord of Admirals appearing within the mind of Chakas during the Battle for Installation 07 and helping to fight for control of the halo.