These theologians include a biblical character (4)
I believe the answer is:
seth
'a biblical character' is the definition.
(I've seen this before)
'these theologians include' is the wordplay.
'include' indicates the answer is hidden within the clue.
'SETH' is hidden in the letters of 'these theologians'.
(Other definitions for seth that I've seen before include "Boy's name" , "Adam and Eve's third son" , "Cain/Abel brother" , "A Starkadder" , "god of Egypt" .)