Vadleány comes from Central European (Hungarian) folklore. She is a forest sprite—her name means "Forest Girl" (literal translation: wild girl) -- who seduces wanderers and steals their strength. She is usually naked and has extremely long hair.
The vadleány appear in the fictional world of El Arcana [1] as woodland nymphets who lure men into the woods and then drain their energy. It also appears to be a not-infrequent pseudonym for teenage girls from Russia or Scandinavia.
References
Vadleany Wikipedia(Text) CC BY-SA