"Chiang Kai-shek was added leader which made Roosevelt,Churchill,Stalin,Kai-shek the Big Four.
Two of them turned agains't us."
Chiang did not turn against the Western Allies.
Before the Second World War, China had been locked in a bitter civil war that began in 1926. The two main opponents were the Communist, CCP, led by Mao Zedong and the Nationalist, KMT, led by Chiang Kai-Shek. When Japan invaded Manchuria both sides declared a cease-fire in preparation for the oncoming Japanese assault.
When Japan finally did invade Chiang had to fight them with his hands tied as he knew full well that once the KMT were weakened the CCP would flare up in Eastern China and take-over. This proved to be correct. When Japan surrendered the KMT were too weak to take on the CCP. Only with US intervention did and Japanese garrison troops did the KMT take back many population centers. But when the peace talks completely collapsed in 1946 the U.S pulled out it's aid, and declared neutrality. This led to full-scale war between the KMT and CCP.
The civil war finally ended in 1949 with the CCP victorious. The KMT with Chiang Kai-Shek at it's head retreated to Taiwan, which leads to the current day argument that Taiwan is a renegade province of China. The KMT still lead Taiwan.
When the CCP took over, Mao Zedong turned his back on the Western World. And created the Red China that we know today.