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…
Believable magic, like ordinary physicis, operates according to some invariable laws that always result in some kind of cost or "bounce back". The grater the magic, the more it should cost the character physically, emotionally, and spiritually.