What can you say about Kyle? Way too much, all of it negative, if you happen to be Jessica! But for everyone else, Kyle is a dashing thief of the Lunar world, later to become one of it's most reknowned heroes after the battles between Dragonmaster Alex and Ghaleon. Of course, it's much easier and more entertaining to just listen to Jessica, but we wouldn't want to embarass Kyle like that.
You can't be a world hero and successful thiff without being able to fight, though, and that's where Kyle really shines. Armed with his suspiciously named Insane Sword and the much more apt Power Up technique, Kyle can cut down foes in record time, with enough left over to throw out a quick quip. Sure, he hasn't done quite that well in the Duelling League, but that isn't Kyle's top priority anyway. At least, it's not until Jessica comes home bragging about her own success, so you can never be too sure when Kyle will show up.