The Fae, they are called, though the reason they are not called by their true name, the Fairies, has been lost to the ages- at least, by the humans. The other races know, the other races know well of the Fae.
Humans have a very short memory. The elves, the dwarves, the goblins, the orcs, they don't. They remember of the interactions between Atheians and the Fae all those years ago in that other age. They know what happened. But the humans... they have forgotten.
This is why they will be the first to die.
A war of ambition threatens the unseelie houses of Thiran Nar.
The blade of the adamant blossom…
The PCs find a small green glass bottle, something can be seen writhing within the smoked glass. If the PCs open the bottle a repulsing form of life will pour forth and grow in size. A genderless beings of soft pliable purple flesh towers before the PCs, it has no detail, no distinguishing characteristics except for a narrow slit for a mouth that holds rows of inwardly curving teeth.