The close mindedness of this gm is absurd.

You run a game for your players. If your player has a creative, interesting, fun idea that they are willing to fight for, who are you to deny them that?

There are no martial arts in this world

Oh, really?

• My character sequestered himself in the deep jungle, watching the animals, over the years he developed a fighting style that mimicked the animals, his acrobatics grew as he trained, working on using the environment to his advantage. He would flip off of buildings like a frog, climb a wall like a spider, dive through the air like a crane and strike as quickly and deadly as a viper, instead of beaks and fangs, tooth and nail, he uses his muscle, his fists, his knees and elbows. He moves as silently as a crocodile in the swamp, and stands still, almost invisible as hidden as a stick-bug.

Who are you to deny me this? An Immature, stubborn, whiny GM, that's who.