There are many different genres of literature out there, but few are as freeing as fantasy. If you want a 14^th century Monk to battle a dragon in 11^th century Europe or have a world filled with animate rocks that sing songs and have six toes on their left hand. Yeah, I said hand.

The fact is every other genre has boundaries by their very nature. You can have a world occupied by interesting lifeforms, but their had better be a space man or an alien or you can't call it science fiction. You can have a dragon in horror, but is better be scaring the crap out of someone or else you can't call it horror.

With fantasy, you're only limit is what your mind can dream up. You can have a dragon that wise and moral or one that pure evil and delights in pillaging the countryside. You can have world where everyone uses swords and magic or one where everyone is a pacifist and the ruler threatens everyone with a rock.

When writing a fantasy story, you have to keep this in mind. If you get too caught up in trying to fit a certain mold or a certain type of character, then your doing your craft and story a disservice. That's not saying you shouldn't create rules for your world, because you should, but don't get caught up in making a “fantasy” story. Write the story you want and put anything in that you think it deserves. In the end, it's going to be your fantasy.