KGBeast, A.K.A. Anatoli Knyazev, is a DC comic book villain and an enemy of Batman.
Anatoli Knyazev AKA the KGBeast, was an extraordinary assassin who was in the employ of the KGB, which is a Soviet Union's secret police and intelligence agency. Knyazev then became a rogue agent. He went on an unauthorized mission to kill ten key people involved with the United States' Strategic Defense Initiative, which was nicknamed the "Star Wars" program. The Soviets decided to warn the American government about Knyazev's plan. Regardless, Knyazev was able to succeed in his mission. He managed this by killing seven of the designated targets. In pursuing his mission, Knyazev came to Gotham City and came into contact with the costumed crime fighter, the Batman.
Justice League Unlimited
He first appears in the episode "Kids Stuff" where he Copperhead, Cheetah, and Blockbuster I try to rob a gold vault but they are all stopped by the Justice League. He later makes a few cameos in episodes as part of the Legion of Doom. In the episode "Alive" he sides against Luthor during the mutiny against him. In the end he is killed in the fighting.
Although not called KGBeast his alter ego Anatoli Knyazev is mentioned as the leader of Soltsevskaya Bratva in the episode "Vertigo". At some point, Oliver Queen saved his life and in return he made Queen a captain in his army. Their first meeting was shown in flashback where they were both shown as prisoners on the ship "The Amazo".