stalwart supporter/ally etc
From Longman Dictionary of Contemporary Englishstalwart supporter/ally etcstalwart supporter/ally etcFAITHFULa very loyal and strong supporter etc → stalwartExamples from the Corpusstalwart supporter/ally etc• Few people could have made a less favorable impression or turned out to be such a stalwart ally.• They are her stalwart supporters in a dosed, oppressive world.