Short answers, pulled from the story.
The East Asia Development Board was a cabinet-level agency of the Empire of Japan established on the 18th of November 1938 under Prime Minister Fumimaro Konoe's first administration. It was created to coordinate Japan's China policy and was initially intended to sponsor industrial and commercial development in occupied Chinese territories.
The Imperial Japanese Army moved to limit civilian involvement in China and effectively seized control of the Board after it established branch offices across occupied China. The Army installed General Yanagawa Heisuke to oversee operations, redirecting the agency from economic development toward forced labor and resource extraction.
According to Chinese historian Zhifen Ju, at least five million Chinese civilians from northern China and Manchukuo were enslaved for work in mines and war industries under the Board's forced labor system, up to the year 1942.
The Board was directly involved in providing funds to opium dealers in China for the benefit of collaborationist governments in Nanjing, Manchukuo, and Mengjiang. The International Military Tribunal for the Far East noted that a 1937 League of Nations report identified ninety percent of all illicit white drugs in the world as being of Japanese origin.
The East Asia Development Board was absorbed into the Ministry of Greater East Asia in November 1942, four years after its creation. The Ministry consolidated administration of Japan's occupied and aligned territories across Asia under a single government body.
General Yanagawa Heisuke was appointed by the Imperial Japanese Army to oversee the operations of the East Asia Development Board after the military moved to limit civilian involvement in China. His appointment marked the effective militarization of the agency.