Fairy-tale fiend (4)
I believe the answer is:
ogre
'fairy-tale fiend' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ogre that I've seen before include "Man-eating giant of folklore" , "Fierce giant" , "One to gobble flesh" , "Terrifying giant" , "Ugly giant" .)