Once we land on Delta Halo in Halo 2, we encounter ancient structures. The structures, however, seem incredibly un-Forerunner. They are made of stone and all broken down, while Forerunner structures are gray metal, with colorful lights, and they never age. Who built them then? Ancient humans? Even the anniversary for Halo 2 mentions this on the description for the map Shrine. “Ruins such as these have raised serious questions about the installation’s former inhabitants.” What do you think?
Because of the Forerunner books, we now know that the structures on Delta Halo and Regret were at least inhabited by Ancient Humans being “raised” on the ring by the Forerunners. Whether or not they built them or the Forerunners did is a mystery, but I think it’s safe to say that the humans used them after being de-evolved by the Didact.
no they look like that because the flood broke out of containment but monitor of the halo neglected it so a huge flood outbreak and the sentinels built the sentinel wall to contain the flood but the monitor was captured by the gravemind and the sentinels could not perform maintenance because they have to get orders from the monitor but the sentinels were initially programmed to fight the flood
Forerunner saga answered this.
Would’ve been a huge question back them.