Lastly, a variant of this thread.
D'Vane Polhill (DaPhatPhantom@msn.com) writes:
There might have been a single specie in the beginning. They were all peaceful. Soon, three groups formed and all of them had different ideas. One group could possibly be the Forerunner. They moved and settled elsewhere. The Covenant remain at their original spot, and what would later become the Flood, moved elsewhere as well. The Forerunner advanced in technology fast.