Master Dufner:
Very well! This is just my opinion, but I suspect that it will be easier for you to first find and kill some of those evil mutants and then investigate. Once your investigation reaches a certain point, howver, I'm reasonably certain that you will encounter a situation you cannot handle by yourself.
Let me introduce you to someone who might be able to assist you. He is currently in hiding, masquerading like any other master, but in his day he was a feared assassin known as "Hawkeye." His targets could never escape his ruthless aim. Take this letter to him and ask him for help.
I have included some additional information about him for your enlightenment. Please be careful that it doesn't fall into the wrong hands.
Also, take this Dimension Diamond. You can trade this Dimension Diamond for something special from the village gatekeeper, and it will help you a lot on your journey.