That is the idea behind my idea of a story line or even a possible universe. In my idea, Hell is very real. It is one of three universes that coexist similtantiously. One universe contains earth and life as we know it. Another (My idea was to name it Well Spring) is filled with those creatures of magic that once inhabited earth and left it taking magic with them. The other (Hell) is filled with demons and monsters whose only goal is to escape from their universe into either ours or into Well Spring. These universes ae connected at several points around the world that can be opened magically. These portals are known points and have guards assigned to watch and guard against incursion.
I do hope someone can take this idea and run with it.