Yeager is one of the main antagonists of Tales of Vesperia. He has a German accent in the English version and an English accent in the Japanese version. Yeager is the leader of the guild Leviathan's Claw and also disguises himself as the leader of the guild Ruin's Gate. Yeager works with certain leaders of the knights throughout the game helping them obtain gald and materials. In truth, Yeager is actually a good person. After the Great War, he adopted two girls, Gauche and Droite. They both wield swords and are always found near Yeager. After you kill Yeager, there is a side quest where you fight Gauche and Droite but do not kill them. They give you one of Raven's most powerful weapons in exchange.
In the Great War, Yeager was actually killed. As was two fellow knights. Raven, one of the knight captains and, Casey, a female knight who both Yeager and Raven loved. Commandant Alexei brings back Yeager and Raven using blastia in place of their hearts. Basically making them imperious to aging. The weapon that Gauche and Droite give to Raven is Casey's Bow.