Azlok

Lord Azlok was leader of the Viperox in 1958. He came to Earth, following Rivesh Mantilax, who had a bioweapon that could be used against the Viperox. He allied with Colonel Stark, who was in the US Army. He had made a deal with Stark, so Stark would aid him in his plan. His base was beneath a ghost town which had been abandoned during the Gold Rush. He had a confrontation with the Tenth Doctor after he had kidnapped his new companion, Jimmy Stalkingwolf. Cassie Rice, the Doctor's other companion, threw a gas canister at him and he was trapped in the flames but managed to escape. He was then betrayed by Stark and he was forced to fly off. He led the assault on the army base, but was repelled when the Doctor modified the bioweapon to make an annoying sound, forcing them to retreat back to Viperon. Before retreating, Azlok angrily shouted, "Your day will come, Doctor!", though the Doctor again dismissed the warning of his approaching death. (TV: Dreamland)