Nietzsche’s Birth of Tragedy and Zarathustra

In the “Attempt at a Self-Criticism” directed towards the Birth of Tragedy, Nietzsche refers to “that Dionysian monster who bears the name Zarathustra.” How does Zarathustra relate to the Apollonian/Dionysian pairing, the music making Socrates, and the metaphysical comfort of tragedy? Is Zarathustra a tragic hero in the Aristotelian sense, and if so, what is his fatal flaw or error? What are the tragic and comic elements of Zarathustra?