A monster spiller of gore (4)
I believe the answer is:
ogre
'a monster' is the definition.
(fairy tale monster)
'spiller of gore' is the wordplay.
'gore' can be anagrammed to 'OGRE'.
However, I am not clear how the anagram is indicated.
Can you help me to learn more?
(Other definitions for ogre that I've seen before include "Monster, troll" , "Wicked and inhuman person" , "Wicked giant" , "Human-eating giant" , "terrible person" .)