Short answers, pulled from the story.
The National Revolutionary Army was officially formed in 1924 by the Kuomintang as its military arm. It was created under Sun Yat-sen's leadership with support from the Comintern and built from pro-Nationalist regional forces.
Chiang Kai-shek served as commander-in-chief of the National Revolutionary Army from 1925 to 1947. He was also chairman of the National Military Council, which directed all military operations and strategic planning.
The National Revolutionary Army fought the Northern Expedition against Beiyang warlords from 1926 to 1928, a series of encirclement campaigns against Communist forces from 1929 to 1934, the Second Sino-Japanese War from 1937 to 1945, and the Chinese Civil War against the People's Liberation Army.
Over its existence the National Revolutionary Army recruited approximately 4,300,000 regular soldiers. Between 1937 and 1945 alone, approximately 14 million men were conscripted into NRA service during the war against Japan.
Under the 1947 Constitution of the Republic of China, the National Revolutionary Army was formally disbanded and reorganised into the Republic of China Armed Forces. Ground units became the Republic of China Army, which retreated to Taiwan in 1949.
The Soviet Union provided early support, including Comintern advisers and, from 1938-82 T-26 tanks. Germany supplied military advisers and equipment during the Nanjing Decade, including German-trained elite divisions. From 1941, the United States became the primary backer via Lend-Lease, supplying Sherman and Stuart tanks and training modernised units known as the X Force and Y Force.