The SS concentration camps were Heinrich Himmler’s creation. He had established the first camp at Dachau and continued to take a close interest in the camps until the end. True, the day-to-day affairs were dealt with elsewhere, first by Theodor Eicke’s Camp Inspectorate, then by the WVHA under Oswald Pohl (who proved to be just as fierce as Eicke). Still, Himmler was ultimately in charge. He received reports and inspected camps. No major initiative could be made without his approval. This explains why Pohl was so devoted to Himmler, as the former Auschwitz commandant Rudolf Höss recalled after the war.
Pohl and Eicke, both very brutal characters, were perpetually in conflict and frequently had violent arguments. They had opposing views on almost every aspect of their work and responsibilities. […]
On taking over the concentration camps [in 1942] Pohl immediately set about reforming them in line with his own ideas. First of all, a number of camp commandants had to go, either because they were not following Pohl’s instructions or […] Pohl took the view that they were no longer up to scratch for a concentration camp. […]
Pohl treated every wish by the Reichsführer-SS as a command!
Pohl was a superior who required the highest degree of commitment and hard work from those under him. He frequently came down on errors and lapses with inhuman severity and was ruthless in enforcing his will. Woe betide anyone who ventured to block his plans. He would not rest until his opponent had been sidelined or destroyed. […]
Pohl treated every wish – and they were not few in number – expressed by the Reichsführer-SS as a command! I have never known Pohl to pause for thought about orders from the Reichsführer-SS, let alone voice any criticism of them. For him an RFSS [Himmler] order was something clear-cut, a fact, and it had to be carried out regardless of the consequences! He was unhappy if anyone puzzled over RFSS orders (which were often very obscure) or spoke of their being impossible to implement. […] In spite of his forceful personality Pohl was the most willing and obedient executor of every wish and plan issued by the Reichsführer-SS, Heinrich Himmler.
Source: IfZ, F. 13/6 (emphasis in the original)
Translation: Lesley Sharpe and Jeremy Noakes