KGB First Deputy Chairman Charkov

Charkov is a senior KGB official who materialises in Valery Legasov's life with the quiet menace of the state itself. He speaks in soft, reasonable tones about loyalty and secrecy, reminding Legasov that his work, his phone calls, even his friendships are watched. He wants compliance, not conversation.

Alan Williams plays him without raised voices or theatrical cruelty, which is precisely what makes him chilling — he's polite, almost avuncular, and that civility is the threat. The character distills the show's real antagonist, an incurious bureaucracy protecting itself, into one calm, watchful man.