Dragon Den in expert dimensions

[JackFrost1111111]

I have gotten 2 dens in 7 floors on expert

[LyNxEfecT]

I see a dragons den every 1-2!floors in expert. And virtually every floor once I hit floor 15-30

[Mentor_MrEUS]

well im on my 2nd week of dimensions and still no dragons dens seen after 2 intermediate dimensions done strated my 3rd inter dim and still no dragons den

They are a random/rare drop, but as others have said, they aren't that rare it seems. Have you cleared all the dark areas in those dimensions and still not found one?