Klaus von Wolfstadt

Klaus von Wolfstadt, from one of the nations of the "Western Alliance," has left his duty as a soldier to his nation in order to be a knight to Taki Reizen, commander of the 15th division "Rozen Maiden" whose country has an alliance with "Eurote," an enemy of the Western Alliance.

(Source: Wikipedia)

Also known as "Mad Dog" and sometimes referred to as the commanders "Loyal Dog" by his men.