obsidian
glass jaw
Both can argue well. It might even get interesting:
http://www.comicon.com/ubb/ultimatebb.php/ubb/get_topic/f/6/t/011062/p/1.html#000000
http://www.comicon.com/ubb/ultimatebb.php/ubb/get_topic/f/6/t/011062/p/1.html#000000