>>96347167
Elves being a young species but still long-lived would almost by necessity have to be an origin story for elves. The first generation of elves that's shown up amidst the other races of the world would live for a very long time, multiple generations of even the long-lived dwarves, likely to the marvel and concern of rival states that may well threaten to stamp out elves before they can even get a foothold.
The closest thing I can think of is a book I read a while back called Inherit the Earth, which follows the story of a girl that was born with strange powers being hunted down by others for her potential as the start of a new species of humanity. For elves to spring up from a world dominated by other races, they either need to be objectively superior in nearly every aspect in order to resist any attempts to quash the new race, or be so integrated/isolationist that no one notices them becoming a powerful faction. Take just about any X-Men plot but replace any reality-shattering superpowers with some kind of spellcasting.