He mananaged to develop the SS into the strongest para-military organisation in the Third Reich. The SS acquired vast police powers in Germany itself and the occupied territories and it also gained primary responsibilities in the areas of security, intelligence gathering, and espionage.
In the final months of World War II he tried to negotiate peace with the Allied forces and planned to succeed Hitler. The latter, after acquiring knowledge of this, stripped him of all his powers and ordered his arrest. Disguised as an ordinary soldier he was captured by the Allies and committed suicide before he could be tried.