In the start of the series, a copy writer (6)
I believe the answer is:
scribe
'writer' is the definition.
(scribe is a kind of writer)
'in the start of the series a copy' is the wordplay.
'in the' indicates putting letters inside.
'start of' means to remove the last letter.
'the series' becomes 'set' (I've seen this before).
'a copy' becomes 'crib' (I've seen this before).
'set' with its last letter removed is 'se'.
'se' placed around 'crib' is 'SCRIBE'.
(Other definitions for scribe that I've seen before include "Clerk, a public copyist" , "One used to copy out documents" , "Writer (before printing was developed)" , "Score" , "One copied documents before the invention of printing" .)