This is the background of Xue Yue, credits to "Brandon Li" from Quora.

"Xue Yue was a Nationalist general who served with Chiang Kai-Shek since the Northern Expedition of 1926. During the Second World War, he fought in the very first major battle of the war in the massive Battle of Shanghai that involved nearly a million soldiers. However this is not what he should be known for.

The following year, in 1938, the Japanese attacked the city of Wuhan in Hubei province which lies on the Yangtze River. This battle was even larger than that in Shanghai and lasted for 4 months. Here, he encircled and nearly destroyed an entire Japanese division, forcing them to airdrop in hundreds of officers to lead the unit after nearly all of its original ones had been killed. This was the only time the Japanese had to utilize such drastic measures during the war in China.

Still, Xue's greatest feat would begin in 1939, when the nearly unstoppable Japanese military had conquered all of the most populous and modernized areas of China in the Northeast. The gate to the Chinese capital at Chongqing was Hunan province and its capital at Changsha. As a result, the Japanese would focus many of their attacks in this region to hopefully find a way to end the war. However, Xue Yue would successfully lead the defense of Changsha for 5 years until the city finally fell in late summer of 1944.

During each major battle, Xue would inflict equal or greater casualties upon the Japanese. This is especially impressive when one knows about the state of the Chinese armed forces during the 1930's and 1940's. The most elite Chinese divisions at the start of the war were German trained and equipped, making them roughly equal in equipment and training to the Japanese but Japanese divisions were triple the size of Chinese ones (24-28,000 vs 10,000). However, these elite units made up only about 80,000 of China's nominal strength of over 2 million soldiers. By the time the battles at Changsha happened, all of these units were completely destroyed. This problem was compounded that China's fledgling tank and air forces were also destroyed in the opening months of the war.
As a result, the bulk of Chinese units during WW2 were armed with unreliable copies of Western rifles, light machine guns, and the occasional mortar. Failing that, soldiers were given swords. To fight against machine guns. Despite all these shortcomings, Xue Yue was still able to hold a city for 5 years against an overwhelming Japanese superiority in firepower.

And he got a happy ending too: the general died in 1998 at the ripe old age of 101 after watching the Republic of China in Taiwan become a wealthy and free nation."