Lenin

He led the Soviet Socialist Revolution that turned world history upside down in the twentieth century.
He created a Marxist-based working class party in Russia, the world's largest and most backward country.
He was the ideologist of politics who overthrew the Russian Tsarist monarchy, the stronghold of reaction, and liberated workers and peasants from the exploitation of landlords and capitalists.
He guided the formation of communist parties in many countries around the world, including India.
He developed Marxism for the imperialist era. He played a leading role in the development of Marxist theories of state, nation, and party structure.