100,043 BCE

In approximately 100,043 BCE, the Forerunner Ecumene Council assigns the Contender-class ancilla 05-032 Mendicant Bias to test Installation 07 near Charum Hakkor. The installation, fired on a system-wide power setting, destroys all neurologically complex life and Precursor structures in the system and accidentally liberates an ancient Gravemind known as the Primordial, which is transported on the ring on Master Builder Faber's orders. Soon after, Faber tasks Mendicant Bias with interrogating the Primordial and Installation 07 is transported in an unknown location. Over the course of their 43-year conversation, the Primordial manages to turn Mendicant Bias against its makers and causing it to join the Flood's cause to destroy the Forerunners.

At the same time the Librarian returns to Earth to index the human species. Sample members of the species are removed from the planet and held on the Ark.