On the sixth day, by treaty, the Pit opens on the Market in the Feywild.
The mortal man asks, “Which market are we in this week?”
The faerie merchants always respond “THE Market! There’s only one, you silly mortal.”
The elf walks by with a sly grin, perfectly at home.
Befuddled mortals visit a forest potion stall. It sat in a swamp last week, an ice field the week before. The terrain is different. The stalls are in the same place. They are manned by the same merchants.
Anything you can think of, and some things that you can’t, are on sale in the Market. Will you pay the price?
The Treaty of Passage applies equally to the Feywild as it does to the Shadowfell. And for the same reasons.