What is "gwyllion"

Gwyllion or gwyllon (plural noun from the singular Gwyll or (Yr) Wyll "twilight, gloaming") is a Welsh word with a wide range of possible meanings including "ghosts, spirits" and "night-wanderers (human or supernatural) up to no good, outlaws of the wild." Gwyllion is only one of a number of words with these or similar meanings in Welsh. It is a comparatively recent word coined inadvertently in the seventeenth century by the Welsh lexicographer Dr John Davies (Mallwyd). They may also be known as mountain fey, fae, or fairies.

Gwyllion was a symphonic power metal band from Kortrijk, Belgium, that was active from 2003 to 2009. Founded by singer Annelore Vantomme and drummer Wouter Debonnet, the band released two studio albums before it split up.