Flawed protagonist — one featuring in another novel (8)
I believe the answer is:
antihero
'flawed protagonist' is the definition.
'antihero' can be an answer for 'protagonist' (antihero is a kind of protagonist). I'm not sure about the 'flawed' bit.
'one featuring in another novel' is the wordplay.
'one' becomes 'i' (Roman numeral).
'featuring in' indicates putting letters inside.
'novel' indicates an anagram (letters in a new or novel order).
'another' anagrammed gives 'anthero'.
'i' placed within 'anthero' is 'ANTIHERO'.
Can you help me to learn more?
(Other definitions for antihero that I've seen before include "baddie" , "Unconventional principal character" , "ignoble character" , "Winston Smith in Orwell's 1984, for example" , "central character, say" .)