I've made Casimir Hohenzollern (1481-1527) Duke of Prussia before, now its time for something better. Say that sons of Elector Joachim Nestor die young and childless. His cousin Casimir Hohenzollern OTOH lives longer (his death from dysentery could be easily butterflyied away). There is still Casimir's father Frederick between him and Electorate, but IOTL Frederick was imprisoned by his power hungry son in horrible conditions under pretext of menthal illness. Frederick was released only after death of Casimir. ITTL his imprisonment would last longer and thus Frederick could die earlier.
So after death of Joachim Nestor in 1535 Casimir became head of House of Hohenzollern and next Elector of Brandenburg. Say, that without dysentery he lives to age 75 (like his dad IOTL) and dies in 1556. What does it mean? Besides being bloodthirsty monster (Casimir was infamous for his cruelty, was responsible for massacres of peasants during Peasant Wars and, as I've already mentioned, imprisoned his own father. No surprise he was called "Bloodhound") he was also staunch Habsburg supporter (IOTL he died fighting on Ferdinand's side in Hungary) and Catholic, unlike his younger brothers, who converted to Lutheranism. Thus we could see Brandenburg staying Catholic (Joachim Nestor also remained Catholic at the time of Reformation). And not only this-as Habsburg ally Casimir is likely to actively side with the Emperor during any analogue of Schmalkaldic Wars (and rather obviously, his son Albert, who was IOTL raised by his Protestant uncle George after Casimir's death, would not lead Protestant forces at Sievershausen). With Brandenburg supporting Catholic side actively, how would Protestants fare ITTL in HRE?
So after death of Joachim Nestor in 1535 Casimir became head of House of Hohenzollern and next Elector of Brandenburg. Say, that without dysentery he lives to age 75 (like his dad IOTL) and dies in 1556. What does it mean? Besides being bloodthirsty monster (Casimir was infamous for his cruelty, was responsible for massacres of peasants during Peasant Wars and, as I've already mentioned, imprisoned his own father. No surprise he was called "Bloodhound") he was also staunch Habsburg supporter (IOTL he died fighting on Ferdinand's side in Hungary) and Catholic, unlike his younger brothers, who converted to Lutheranism. Thus we could see Brandenburg staying Catholic (Joachim Nestor also remained Catholic at the time of Reformation). And not only this-as Habsburg ally Casimir is likely to actively side with the Emperor during any analogue of Schmalkaldic Wars (and rather obviously, his son Albert, who was IOTL raised by his Protestant uncle George after Casimir's death, would not lead Protestant forces at Sievershausen). With Brandenburg supporting Catholic side actively, how would Protestants fare ITTL in HRE?