Thanks for the correction. Did think that the Blackshirts were part of the SA but forgot about the later split.
It is like the Bolsheviks killing the Trotskyites. Mensheviks, etc. Last man standing concept - wins all the marbles and the power.
There was talk of unifying the SS, SA and Gestapo under one commander. In front of Himmler and Hitler, Ernst Roehm suggested that it ought to be him. That was not long before the Night of the Long Knives. Perhaps having been Hitler’s superior in the Freikorps made him a bit too bold.