Elves

The elves (Albe or Alpe) are the royal lines of the Fee, and in response to the spread of humans, have largely retreated back to their own world - Albenheim. Retreated, but not given up on taking revenge. They are said to sometimes carry out attacks against people who are asleep, though the purpose of doing so is unclear. They also steal children, and replace them with changelings. In the case of a certain Pied Piper - active in Markwald over a century ago - they do so en masse. Rumors have it that they control leaders of the heretical sects, and may ultimately be responsible for the Totentanz, and the Wild Hunt.
The two clans of elves - light (Eladrin) and dark (Shadar Kai) are the two 'subraces' known in Markwald, though it is not clear that one is more favorably disposed toward humans than the other. The elves have their defenders, who argue that they are not evil, just misunderstood. Whatever the case, when they walk abroad in the world, elves are typically in disguise. Some changelings grow up to be half-elves, whose elven parents makes their desires and instructions evident, at some point.
Two elves have been encountered to date - Edelweiss and Klawuhn. The former appears to be related to Franz der Schwarzhoffen, Cilly 'Wechselbalg' and Edda "Eddi" the Fisher.