Advent of the One-Handed Swordsman

A man finds himself in a desert, his right arm gone. He has no memory of who he is or how he came to be there. All he knows is that there is a sword next to him and an answer to his questions. Who is he? Why is his arm gone? Who would want to do this to him? Follow this one-armed swordsman as he travels this path to grow from being nothing more than a beggar, to a demon who even gods would fear.