Answer
During the Second Sino-Japanese War, Kang Sheng emerged as a trusted ally of Mao Zedong. As head of the Communist Party's secret police, Sheng played a crucial role in suppressing dissent and eliminating political rivals, solidifying Mao's authority within the party. His ruthless tactics and unwavering loyalty earned him Mao's favor, establishing a close partnership that would shape the course of Chinese history.