I guess this sums it up:
King: Wanderer! Thank the gods you've come! The prophecy told us that a mighty warrior would arise, worthy of wielding Fjalnir, the God-axe, and slaying the evil Demon Prince Synraith. We believe you to be that warrior. What say you, traveler? Will you accept this task?
Me: Yea, verily I shall accept thine task and vanq- wait, Synraith? Fiery dude in a floating city? Cape made out of screeching souls? Ahhh, shit. I already killed that guy.
King: You ... already slew the Demon Prince, the Knife in the Dark, the Void at the Heart of All Men, whose identity you did not learn until just now?
Me: Yup. I saw that castle