Officers in reserve prepared retreats after fighting (4,7)

'officers in reserve' is the definition.
The answer and definition can be both people as well as being plural nouns.
Perhaps you can see a link between them that I can't see?

'prepared retreats after fighting' is the wordplay.
I cannot quite understand how this works, but
'prepared' could be 'game' (I've seen this before) and 'game' is found within the answer.
'retreats' could be 'dens' (I've seen this in another clue) and 'dens' is found in the answer.
'fighting' could be 'war' and 'war' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...

Can you help me to learn more?