Part of warfare's ultimate outcome (6)
I believe the answer is:
result
'outcome' is the definition.
(I know that outcome can be written as result)
'part of warfare's ultimate' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'RESULT' is hidden within 'warfares ultimate'.
(Other definitions for result that I've seen before include "'Outcome, upshot (6)'" , "'Outcome, consequence (6)'" , "End - issue" , "Consequence in Ulster (6)" , "Final outcome" .)