Thank you to everybody for the great feedback !!
I thought this : off the city there is an invisible / concealed by a powerful illusion island , the nest of the main bad guys . The city is ruled by a group of evil monsters ( mind flayers , beholders ,the surathi (thanks ! )and aboleths , who occupy the underwater section of the island ) .
The city seems normal at first glance , but there are many strange events :
- a realtive heavy percentage of misshapen humans ( offspring of the surathi )
- many missing people ( kidnapped by the evils for sacrifices e/o experiments )
- no temples of good deities : only neutral & evil , the Good ones preach in clandestinity
- The Black Ravens rule with an iron fist
What do you think ??