Storyteller backed main work (5)
I believe the answer is:
aesop
'storyteller' is the definition.
(Aesop is an example)
'backed main work' is the wordplay.
'backed' shows that the letters should be reversed in order.
'main' becomes 'sea' (the main is an old name for the sea).
'work' becomes 'op' (common abbreviation for 'opus').
'sea' reversed gives 'aes'.
'aes'+'op'='AESOP'
(Other definitions for aesop that I've seen before include "A pose by Greek writer of fables" , "Author of many fables" , "Greek father of fables" , "Fabulous man" , "Greek author of fables (c 620-560 BC)" .)