Not that we’ve finally seen what the harbinger is, what are you all speculating about its backstory.
I think it could be covenant with its own motives for working with the banished or a forerunner experiment gone wrong.
If we don’t kill the harbinger in infinite’s campaign I think it will likely take over the banished forces on the ring after the player defeats whose name I cannot remember how to spell.
Probably Covie fringe, they were never given the respect they deserved by Covenant (sort of like how grunts were pre rebellions) then Atriox was impressed by them and made Harbinger a commander or some sort, I don’t think they have many real ties to Forerunners but we’ll see.
Lots of people/species probably disagree with the mantle, especially the more peaceful species (we humans are great at blowing up, but surely this will have a negative impact on how many species perceive us)
Precursors actually showing up would be bananas, but highly doubtful we’ll see them in game (they’re basically flood though, so there’s that)
I have a feeling it’s a composed Human from when humans lived on the ring.