/jp/ - Otaku Culture

How about such a setting:

The place is real Earth. Up until <today>, it is identical to our Earth.

The time is in the future, perhaps 100 years forward.

There has been some global disaster so:
* Human population has been decimated
* Human technology and organizational structure has mostly regressed to post-apocalyptic levels
* And also monstergirls have invaded Earth through portals

That would combine modern tech and fantasy abilities quite neatly, I think. As it is with post-apoc, there would be a lot of license for a storyteller to pick and choose what knowledge and technology remains in abundance, what is rare and what has been destroyed entirely.