Editor enthralled by remarkably pious king of Thebes (7)
I believe the answer is:
oedipus
'king of thebes' is the definition.
(I've seen this before)
'editor enthralled by remarkably pious' is the wordplay.
'editor' becomes 'ed' (abbreviation).
'enthralled by' indicates putting letters inside ('enthral' can mean 'capture').
'remarkably' indicates anagramming the letters (I've seen this in other clues).
'pious' with letters rearranged gives 'oipus'.
'ed' going inside 'oipus' is 'OEDIPUS'.
(Other definitions for oedipus that I've seen before include "legendary riddle solver" , "King known for complex" , "Mythological king who killed his father and married his mother" , "Legendary Greek king with mother complex" , "Theban who married his mother" .)