I'm considering running a campaign where I want the players to transition from the Feywild to the Underdark.
I've read through the Faerûn campaign setting and I can't see anything. The reason I want to make this transition is as a convenient way out of Returned Abeir, and also so they can fight their way up through the Underdark. It makes sense to me that if they enter the Feywild, then left ending up in the Underdark, there would need to be some cross over point in the Underdark. Does such a place exist? Or do I have free reign to make one up?