Hercule's creator (6)
I believe the answer is:
agatha
'hercule's creator' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for agatha that I've seen before include "...... Christie, author" , "- - Christie (lit.)" , "-- Christie, English novelist" , "- Christie, twentieth century crime novelist" , "...... Christie wrote great detective stories" .)