Despite being creations of the Architects, The Precursors turned their powers against them, challenging the Architects in a war for control of reality. Little is known about the war itself, but in the end, the Architects were victorious. All that remained of the Precursors were various relics, including "a vast fortress labyrinth; a sword one thousand feet long, half-buried in the petrified corpse of a forgotten colossus; and many other strange wonders."
Despite their defeat, some Precursors seem to have survived the war and have returned to claim Evenor. It is speculated that they were responsible for setting the Gloom upon Evenor and, with the absence of the Arcs during the Gloomfall, have slain the Architects themselves.