Check to include final volunteers for conflict (8)
I believe the answer is:
vendetta
'conflict' is the definition.
(vendetta is a kind of conflict)
'check to include final volunteers for' is the wordplay.
'check' becomes 'vet' (I've seen this before).
'to include' means one lot of letters goes inside another.
'final' becomes 'end' ('end' can be a synonym of 'final').
'volunteers for' becomes 'ta' (I can't explain this - if you can you should give a lot more credence to this answer).
'vet' enclosing 'end' is 'vendet'.
'vendet'+'ta'='VENDETTA'
Can you help me to learn more?
(Other definitions for vendetta that I've seen before include "Violent feud" , "A prolonged feud, associated with Sicily" , "Murderous feud" , "ongoing row" , "intense feud" .)