The fellow has me back in his clutches and he's evil (5)
I believe the answer is:
demon
'evil' is the definition.
(I've seen this before)
'the fellow has me back' is the wordplay.
'the fellow' becomes 'don' (both can mean an academic).
'has' means one lot of letters goes inside another.
'back' says the letters should be written backwards.
'me' written backwards gives 'em'.
'don' enclosing 'em' is 'DEMON'.
'in his clutches and he's' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for demon that I've seen before include "Fiend, devil" , "Wizard" , "Familiar" , "Expert" , "Ghoul" .)