黒幕
behind-the-scenes fixer
behind-the-scenes player〔【直訳】舞台裏の演技者〕
behind-the-scenes string-puller
the boys in the backroom(政界の)
eminence grise〈フランス語〉〔【複】eminences grises〕
gray eminence(政界の)〔【同】eminence grise〕
insiderdom(政界などの)
mastermind(計画などの)
the mastermind behind the scenes
Mr. [Mister] Big〔【略】Mr. B〕
a power broker(政治の)〔【同】broker〕
a puppet master〈比喩的〉
puppeteer〈比喩的〉
string-puller
wirepuller〈俗〉