Hentai
Umbar does not know Hentai as yet. While there are demons and monsters, none of them have any interest in molesting anyone (except perhaps to eat them). While sex is not unknown in this world (after all, people have to come from somewhere) it is simply not considered this important. It is more important for many to win that tournament, become a better martial artist or to gather
even more gold by slaying monsters.
This is changing, however. There are no confirmed reports, but certain rumors have started to spread, of a bus full of perverts, a group of molesting schoolboys, plants that try to rape their owners, some strange drug that temporarily turns people into slavering sex maniacs.
So far these rumors are all just that - rumors. No evidence has been found yet, and nobody has bothered looking into it yet. So whatever is behind these rumors can continue its plans.