The positions of the eight God-Kings of Hell were not something any mortal could ever hope to comprehend.
Each one of their ranks had existed since the earliest creatures of flesh gained sentience and learned to sin. They were born of our flaws, given shape by our misdeeds, and inaugurated into perpetuity by our vanity.
They were not names of singular beings but 'ideas' brought manifest. They could neither be killed nor stopped, not in any real sense. They always had and always would be lurking in the shadows, just outside the bounds of comprehension, hatching their vile plans.
All one could hope to achieve was the postponement of their inevitable arrival as much as possible. And more often than not, that was only possible when they would take physical form for the first time into pure and willing hosts. (Read CH 601 for details)
If the host was destroyed in both body and soul before it was besmirched by the darkness, only then would the there be some hope for the world.