A Greek character records some evil ones (7)
I believe the answer is:
epsilon
'a greek character' is the definition.
(letter from the Greek alphabet)
'records some evil ones' is the wordplay.
I cannot really understand how this works, but
'records' could be 'eps' (EP is a type of record) and 'eps' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for epsilon that I've seen before include "character in Greece" , "5th letter of the Greek alphabet" , "Greek character" , "foreign letter" , "Fifth brightest star in a constellation" .)