Arcane criticism of setter is a little excessive (6)
I believe the answer is:
mystic
'arcane' is the definition.
(thesaurus)
I don't understand the rest of the clue.
(Other definitions for mystic that I've seen before include "One attaining high levels of spirituality" , "Spiritualist" , "Paranormal, mysterious" , "One seeking God through contemplation" , "Sixth sense believer?" .)