Sounds great actually.So who are the new Shadow army candidates from campione?? You could even kill other campiones and add them to the army. Marquis Voban or Salvator doni would be a good addition as a shadow.
It's a great idea but please don't strengthen the world like crazy again. I watched its manga and anime. It's not very good. It's average at best. Finish it faster than that. Then you can do a second arc and go to the gods in the manga events. If you get the ones in the first anime.