Dryad
The Dryads live inside the oldest and largest trees in the world rather than under them, and they have never seen a reason to make travel through their forest easier for anybody. The Greenmantle has no roads. This is not an oversight.
They are peaceful, reclusive, and extremely slow. A Dryad conversation can take a season. A Dryad decision can take a century. Petitions from the Eternal City are received with perfect courtesy and answered after the petitioner has metamorphosed, retired, or died.
Appearance
Bark-textured skin in browns and greens, hair like moss or fine root, and leaf-shaped wings that change color with the season and are shed and regrown annually. Elder Dryads grow visibly into their trees over the centuries, until it is no longer clear where the Faerie stops.
Attuned Magic
Nature. A nascent Dryad coaxes growth, closes a wound in bark, and speaks with the plants in reach. A powerful one moves a thicket to block a road, camouflages a whole grove, hardens wood past the strength of stone, and carries a message tree to tree across the entire forest faster than a courier could fly it.
Society
There is no city and no ruler. There is the Heartwood, a ring of the oldest trees in the world where the elders — Eldest Thanewood foremost, though he has not spoken in sixty years — hold council on a timescale that makes the Kingdom's politics look like weather.
Relations
The Greenmantle is the least exploited Faerie land and the one the Kingdom most wants. Its timber, sap, and growing-magic would be worth an empire, and the Dryads' refusal to trade in them is officially framed as backwardness. Anyone looking for evidence of what the Kingdom does to land it has decided is being wasted should look at the Greenmantle's shrinking southern edge.