The Palaeoboreanic peoples, more informally called the Palaeoboreans or simply “Boreans”.
They were us before us. Humans, before humans. They managed to acheive a quasi-medieval level of technology when our own ancestors were still banging rocks together. They flourished for hundreds of thousands of years. Then, for reasons unknown, they vanished. We are what evolved to take their place.
Homo sapiens borealis. These are more-or-less the "humans" of the story, although they're distinct from anatomically modern Homo sapiens sapiens. It is likely the Boreans or very recent ancestors thereof who were the ultimate progenitors of the Fairish races.
The Boreans likely arose when a Baltic subspecies of Homo erectus, known as H. erectus borealis, some of which had migrated south into central Europe during the Gunz glaciation, interbred with Homo (sapiens) antecessor or early Homo (sapiens) rhodesiensis.
The ancient Borean people were a pristine civilization in the truest sense of the word, having developed from a palæolithic level of technology to what we might consider a roughly “Renaissance-level” of technology, entirely independently of later H. sapiens.