Heaven and Hell done with "Ink"
This is the perfect depiction of the crossing or border between the two realms or at least the way I would see it.
The rocky crevasses and mountain ranges making it impossible to cross from the one realms to the other. If you happen to cross from one to the other you'd be met by the guardians watching over each of the realms.
The one fighting with spirit and the other with blade.
I think it's only fair to give the blade a name.
I would like to call it the "Jagged Soul Twisted" because of all the twisted souls it has consumed and will still consume.
The castles of the undead army watching silently over the no mans land. Waiting for a battle that is coming sooner than later. But are they ready to fight a war that is unwinnable.
Castle upon castle and fortress upon fortress is bound to fall someday!
Empires dont last, they all fall eventually
Artwork done with Wonder the mobile application which is in turn self generated AI artwork..
Probably one of the easiest to use