Short answers, pulled from the story.
The Mukden Incident occurred on the 18th of September 1931 when Japanese Kwantung Army officers detonated explosives on a section of the South Manchuria Railway near Shenyang. This event served as justification for Japan to invade the region and eventually establish the puppet state known as Manchukuo.
Puyi arrived in Manchuria in March 1934 to assume his role as head of state and became Emperor Kangde of the Empire of Manchukuo. Despite holding the title of monarch, Puyi possessed no real political power because all decisions were made by Japanese military officials stationed within the government.
Manchukuo became an industrial powerhouse through state-directed planning and heavy investment in military infrastructure managed by the South Manchuria Railway Company. Steel production exceeded Japan's output during the late 1930s while Nobusuke Kishi pioneered an elitist system allowing private zaibatsu corporations to invest in the region.
The population of Manchukuo grew dramatically from 15,834,000 residents in 1908 to 50,000,000 by 1941 with ethnic Chinese constituting approximately 96% of the total population. The Japanese government planned to emigrate five million people to Manchukuo between 1936 and 1956 but only about 200,000 young farmers arrived between 1938 and 1942.
The Soviet Red Army invaded Manchukuo on the 8th of August 1945 leading to rapid collapse of the entire military structure and the abdication of Puyi on the 17th of August 1945. Puyi hoped to escape to Japan but was captured by Soviets instead and later extradited to the Chinese Communist Party government when it came to power in 1949.