Jun locks his armor, and then after reach explodes, he keeps his armor locked and flies over to onyx right before it turns into the dyson spear where he joins forces with the onyx sentinals to fight the Nelkrons who are an ancient enemy of the fore-runners, but were eventually defeated and all trapped inside a giant prison until the halo array fired which freed them.
The nelkrons are biomechanical life forms with the power to convert energy to matter and matter to enercy at will. They are able to mutate any way they want, but their appearance generally esembles a mechanical humanoid with a birdlike head. Somewhat similar to the myrs from magic the gathering.