[@DepressedSoviet]
I suppose I would go for a Prussian character who despises the Austrian in command and believes that salvation of Germany can come through the assassination of Hitler after the destruction of his character least he be made a martyr for his cause. The last thing the Prussian would want is a spike in Nazism and he'd like this to be carried out before the Soviets decide to invade the old Prussian capital again and take it for themselves, fearing the post 1944 scenario that comes to life in 1945 where the Red Army brings the atrocities of Prussian Nights to life. 

More than anything he wants to save what is left of East Prussia [as he was born in Königsberg] but if not then to prevent the Soviets from taking Brandenburg whole. This would also mean that he would attempt to get the United States to enter and take Berlin before the Soviets ever could. If obtaining this goal means lying to the Soviets and giving up East Prussia then he is willing to do it so long as the core of Germany is preserved under allied control as opposed to the Comintern. Hopefully from there Germany could rebuild and look to hold its own against the communists that the world once disapproved of more than Nazism.

The Prussian himself would possibly be involved with the Oberkommando der Wehrmacht, being an officer higher up with a ranking high enough for him to obtain crucial information with ties in the Luftwaffe. He would actively work to prove himself a nationalist that has no doubts in his country despite his secret hatred for the Nazi ideology in public. He believes in Germany, but he does not want a German future  under communist rule or Nazi prowess.

Serious, brave, and stalwart in his beliefs he will fight to free Germany in the best ways he can using both in intelligence and armed conflict.