Vladimir Lenin massacred more than 1 million people for political or religious reasons, murdered up to 700,000 in the genocide of the Cossacks, more than 15,000 peasants in the Tambov rebellion, over 3,000 sailors and civilians in the Kronstadt rebellion, thousands of workers who dared to strike or could not work, almost 2 million who died in the Gulag concentration camps and upwards of 8 million from famine and disease.
Source: David Josef Volodzko via The Truth About Vladimir Lenin a Century After His Death