Nietzsche - Zarathustra, the savior of the modern era

Why did Nietzsche choose the character of the Eastern Persian Zoroaster speaking in his name? And why did he craft his phrase in a style similar to the style of gospel writing? Why did he face criticism that he did not face in any other work? Was the book the cause of his madness, as some claim? Why did he attach the title directly to the phrase "A book for everyone and no one"? This book contains lectures delivered by Carl Gustav Jung over five years (1935-1939) about the book "Thus Spoke Zarathustra." Readers may be divided between supporters and opponents, and they may find some difficulty in understanding Jung's interpretations of Nietzsche's personality, but his many extensive digressions make this book a mental encyclopedia that goes beyond psychoanalysis to include information and ideas in philosophy, literature, mythology, official and unofficial religions, as well as some political issues at times.