The problem is that you cannot prove yourself against...

The problem is that you cannot prove yourself against someone who is much weaker than yourself. They are in a lose/lose situation. If you are strong and fighting the weak, then if you kill your opponent then you are a scoundrel... if you let him kill you, then you are an idiot. So here is a dilemma which others have suffered before us, and for which as far as I can see there is simply no escape.