Adolf Hitler was the man who took control of Nazi Germany and in general started World War 2 and the Holocaust. He was the "Fuhrer" or leader of Germany at this time. He was considered a great leader to the German people and had a lot of charisma and a great speaking voice, which made it easy for him to tide the German people over to the Nazi party before he controlled Germany. Before he was the leader of the Nazi party he was in the army and was a very highly regarded soldier, and this heped Hitler take control of Germany. One of the biggest things that allowed him to take control of Germany was the treaty that was put on Germany after World War 1. which took almost everything away from the Germans. Adolf Hitler and the Nazi party basically took control of Germany in 1933, when Hitler was appointed chancellor. Hitler and the Nazi party in general was very anti-semite (Anti Jew) which led to the destruction of so very many Jews. They also thought that the Aryan (German) race was superior to any other, which was one of the reasons why not only Jews were killed. Hitler committed suicide in 1945, when he was certain he would lose the war.
Heinrick Himmler was the leader of the SS (the German Police). Originially the SS was part of the SA, at that point Himmler did not have the power he wished to have, and craved more. The Night of the Long Knives (which was about the destruction of the SA) allowed him to gain this gaol, and in the end he only answered to Hitler directly. Hitler gave him the order to destroy the Jews, and he chose the Death Camp Auschwitz to do just that. I am not sure how or when he died.
Hermann Goring was the Commander-in-chief of the German army, and was the successor to Hitler. Before that he was an ace fighter pilot in the army, and was fairly famous because of it. He was said to create the German Jet, and other weapons that the Germans used, but people considered him to be quite an idiot as he made a lot of military blunders and such that if he did not do, Germany may have won the war. He ended up being captured and being sent to the Noreburg trials, where he committed suicide before his trial took place.
Adolf Eichmann first joined the Nazi party because his friend, Ernst Kaltenbrunner suggested it. He found a lot of interest in things Jewish, and he ended up being the Nazi's "Jewish expert". It was him who had to ultimately decide the "Final Jewish Question". He controlled the killing of many many Jews during The Holocaust and during the Noremburg trials and was sentenced to death and hung on May 21, 1962.
Reinhard Heydrich was one of the most evil and cold people in the ranks of the Nazi's. He quickly rose through the SS ranks and ended up second in importance to Heindrich Himmler in the SS and he was one of the planners of the Final Solution along with Eichmann. He was once accused of being a Jew, but he impressed Hitler so much that he was able to stay in the Nazi party even though there was a small chance he could have been a Jew. He was assassinated by Czech underground agents on May 27, 1942, well, he didn't die, but he was mortally wounded and died a few days after.