Why won't Dirty Butory fight me?
 

There is this mini boss called Dirty Butory that I found near the Furious Paladin's castle. He has an army and everything and even lets me put the fighting swords icon on him, but whenever I get to him, I get this message box that says that I thought he was a vendor and I wish he would have told me before I went to him.

Why can't I fight him?

You can get a quest about him from one of the toads.

There are three toad leaders in Marshan Swamp who all want various things from you in their contest for supremacy. One of them will ask you to get something from Dirty Butory, which involves killing him. :-P