Hitler was a German Dictator in the times of the NAZI political party, he was anti-Semitic and wanted a "perfect race". The answer to your question is as follows;
Why did Hitler hate? A; He was an evil man who believed if you did not fit his political agenda you should be killed.
Why did he kill them? A; He killed them to try and wipe any race and religion he didn't agree with off the earth.
How did he die? A; Rumor as it he committed suicide after being surrounded by Allied forces.
Hope this helps!