Origin is Teutonic the Hulden are German hill fairies led by Hulda and serving as her entourage. Their fortunes have risen and fallen with hers. Once upon a time, they were considered beautiful, volatile, but potentially generous dancing spirits. Post-Christianity they were reclassified as malevolent female demons, the proverbial wicked fairies. This may be propaganda intended to discourage contact and veneration. Hulden should always be addressed respectfully. They can be helpful and friendly but have a tendency to be temperamental they can be punitive spirits as well.
Judika Illes, Encyclopaedia of Spirits the ultimate guide to the magic of fairies, genies, demons, ghosts, gods and goddesses, 2009, Hulden, p 497