Strong figure taking on long conflict (8)
I believe the answer is:
stalwart
'strong' is the definition.
(thesaurus)
'figure taking on long conflict' is the wordplay.
'figure' becomes 'stat' (statistic).
'taking on' is an insertion indicator.
'long' becomes 'l'.
'conflict' becomes 'war' (war is a kind of conflict).
'l'+'war'='lwar'
'stat' going around 'lwar' is 'STALWART'.
(Other definitions for stalwart that I've seen before include "stout" , "Steadfast" , "Indomitable" , "Walt's rat is strong and brave" , "Valiant" .)