Fey crossroad

Fey crossroads were magical portals, many of which led to the Feywild. They could be found all over Toril but many were hidden from casual view. They often required the use of a ritual to operate and after the Spellplague many malfunctioned.

Description
A fey crossroad, according to druids, was where a fold in reality's ends touched each other, thus allowing instant travel by stepping in end and coming out of the other. Each crossroad had a fey guardian called crossroad guardian who had to be convinced to use the crossroad, fey got automatic permission.

As a general rule, entrances were hidden from sight, and required the detect crossroad spell to find, though druids often marked them by arranging stones in circles, lines or other ways. Most were large enough for a huge creature to fit through.

They were mapped by druids and known to some bards, to other people crossroads were more the stuff of legends than anything else.

Usage
To use a crossroad one needed to find one first, which required the aforementioned detect crossroad spell. After finding the crossroad guardian needed to be asked for permission for usage by every person individually. The guardian could give or not give permission as seen fit. Fey didn't need to be given permission, they used a crossroad whenever they wanted.

Travel
The most notable use of a crossroad was to travel from one end of the crossroad to the other end in an instant.

Interestingly, one could travel via crossroad without the traveler's intention, by accidentally stepping into a crossroad and coming out of the other end. Usually, this happened when the crossroad guardian gave unwanted permission to use a crossroad due to being impressed by the traveler's singing which was mistaken for a plea to enter the crossroad.

Communication
Another use of a crossroad was to send acoustic messages through one end of a crossroad to another end. Druids maintained schedules to send information to other druids.

Impossible uses
Sound and people, if given permission, could travel through, but interestingly one couldn't attack, in mundane or magical ways, to get through a crossroad to hit a far away place.

It was also impossible to get visual information of the destination through a crossroad.

Guardian
A crossroad guardian was an artificial fey with the duty to guard a crossroad. One guardian was stationed at each end of the crossroad.

With increasing urbanity of the crossroad's area, a guardian grew increasingly hostile towards would be users of its crossroad.

They had a weakness for music, which was why bards had it easier to get permission then others.

People who wanted to use a crossroad couldn't just kill a guardian and get through because a crossroad without a guardian ceased to function as an entry, it could be still used but only one-way from the other side, given the guardian there wasn't killed beforehand.

Creation
Druids could cast the create crossroads and backroad spell to create a new crossroad with two ends and one crossroad guardian at each end.