Klaus von Hertzon (original version: Klaus Von Hertzen (クラウス・フォン・ヘルゼン Kurausu Fon Heruzen)) used to be the second-best Bakugan player before he lost to Dan Kuso, which caused him to drop down to fourth place. Klaus was first seen in Bakugan Battle Brawlers and became a supporting character in Bakugan: New Vestroia.