The Harbingers have no AI or sentience; they are superweapons. Only the Queen can control them. From what we know, their attack seems to involve attaching a Void projectile to enemies, which then explodes. The Warminds were Golden Age AI's, the knot known surviving one being Rasputin. They fought the Darkness and failed, but Rasputin shut down solar defenses and let the Darkness in, knowing that either many had to die, or humanity would be one extinct. I'm not sure what Rasputin is doing, Oryx-wise. And since the Harbingers are controlled by the Queen, I'm not sure why she doesn't deploy them. That was probably her plan, to get close to the Dreadnaught and then release them. But the Awoken faced serious resistance and Oryx's massive shockwave weapon