where do you get the Dark Elegance dress?
Try puzzle zones and buried treasures. Most optional stuff is in them.
ive tried all of them and have not found it
This just means you didn't check them all :)
is it in the cave that smells lewd? if it is then how do I get inside? do i need a high lewd level to get in?
No, that cave is just a decoration so Idris would have a "home".