Casper was outwardly relaxed, but his mind was entirely focused on his opponent. When the slashes from the katana and the strike of the whip came, he sprang suddenly into action, his reflexes perfectly timed. He leapt out of the way of the katana strike with ease, then side stepped the whip, his grin growing more wild. It was almost feral now, wide and tooth, and if one looked closely, they would notice that his teeth were now pointed as well. The hair on his head that was normally rather wild looking, yet laid generally flat, was now rising, as if a charge of energy was flowing through it, like the hackles of a cat. He dodged the two following strikes as well, stepping quickly to avoid them at the last second, getting a little bit close each time he dodged. Then Keith dropped into a defensive stance, his whip swinging through the air above his head with rapidly growing speed. 

Now Casper's features were even more animal like. His eyes were no longer the same sharp green, but the pale green of a cat, and his nails were suddenly longer and sharp. like claws. His feral smile had not faded at all and he spoke through the grin, his eyes locked onto his opponent. "Oh yes, I'm enjoying this very much. It's so much fun to play with new toys." He didn't listen to what the man was saying about the whip. He wasn't concerned. He sprang forward, but he didn't run like a human, but low to the ground, staying on his feet, but occasionally using his hands as well as he got in low and struck out with his sharp nails at Keith's middle.