The Jews were sytematically killed during the years 1941-1945. Other undesireables (apart from Gypsies) were not systematically killed.
1941
It was called the T-4 programme, it was a pre-cursor to the Holocaust and the Final Solution.
He killed most of them.
It meant that Hitler no longer controlled Europe and Japan no longer controlled the Pacific.
concentration camps
He always did since the lost of ww1, he wanted revenge on the jews but once he came to power in 1933, he putted his imaginations into action
The killing units were part of his Final Solution and dream of a pure Aryan European world controlled by him. He eliminated a lot of undesirables with his mobile killing units.
The final solution
They were sent to concentration camps ...
Six million Jews and five million "undesirables" were killed in concentration camps or elsewhere. The undesirables were people Hitler deemed not welcome in the pure Aryan Europe he dreamed of ruling. They were mentally ill, feeble minded, dwarves, human with anomalies and deformities, communists, Hitler's enemies, and anyone else he chose to throw in the concentration camps and extermination camps.
It is generally considered that Hitler decided sometime between the summer of 1941 and the summer of 1942, but as he never wrote it down, it is hard to say with total conviction. One other leading theory is that the decision was not made until 1943, after 4 million had already been killed. Most of the decisions to kill the groups other than the Jews were made late in 1944 or 1945.
Germany was controlled by the dictator Adolf Hitler in WWII.