Force brings victory to fellow soldiers with keys (9)
I believe the answer is:
vehemence
'force' is the definition.
(thesaurus)
'victory to fellow soldiers with keys' is the wordplay.
I cannot really understand how this works, but
'victory' could be 've' (VE is short for Victory in Europe) and 've' is found in the answer.
'fellow' could be 'he' ('he' refers to a man) and 'he' is found within the answer.
'soldiers' could be 'men' (men can mean a group of soldiers) and 'men' is located in the answer.
This explanation may well be incorrect...
'brings' acts as a link.
Can you help me to learn more?
(Other definitions for vehemence that I've seen before include "Passion" , "Expression of forceful feeling" , "Vigour of expression" , "Forcefulness" .)