Short answers, pulled from the story.
Hirohito, known posthumously as Emperor Showa, was the 124th emperor of Japan in the traditional order of succession. He reigned from 1926 until his death in 1989, the longest reign of any emperor in Japanese history.
Hirohito reigned from 1926 until his death on the 7th of January 1989, a span of 63 years known as the Showa era. He became emperor when his father Yoshihito died on the 25th of December 1926.
General Douglas MacArthur believed a cooperative emperor would help secure a peaceful Allied occupation of Japan. He therefore excluded evidence that could incriminate Hirohito from the International Military Tribunal for the Far East, and responsibility for Pearl Harbor was attributed to Hideki Tojo instead.
In the radio broadcast of the 15th of August 1945, Hirohito described a new and most cruel bomb whose power to do damage was incalculable. He warned that continued fighting could lead to the total extinction of human civilization and ordered the Japanese to endure the unendurable.
Historians dispute the exact extent of Hirohito's involvement, though most now agree he was deeply involved in political and military decisions. He authorized chemical weapons against the Chinese on 375 occasions during the 1938 invasion of Wuhan, and sanctioned the Three Alls scorched-earth policy linked to more than 2.7 million Chinese civilian deaths.
Hirohito died of duodenal cancer at 6:33 in the morning on the 7th of January 1989, at the age of 87. He had undergone pancreatic surgery in September 1987 and suffered continuous internal bleeding before his death, after which he was buried in the Musashi Imperial Graveyard in Hachioji, Tokyo.