Anton Fellner served as a captain under Imperial Duke Otto von Braunschweig on Odin during the late Goldenbaum Dynasty. In 796 UC, he took part in the operation to arrest Marquis Klopstock following an assassination attempt on Kaiser Friedrich IV, voicing concern about potential damage to a statue of Kaiser Rudolf at the entrance to Klopstock's estate. When the Lippstadt Rebellion erupted, Fellner initially backed Duke Braunschweig. He proposed assassinating Reinhard von Lohengramm, but Braunschweig rejected the plan, desiring instead to defeat Reinhard in open battle. Ignoring orders, Fellner proceeded with his plan but was stopped by Reinhard’s security forces. This unauthorized action caused Braunschweig and other nobles to flee Odin, while Fellner surrendered. Disillusioned with Braunschweig, whom he described as “casting pearls before swine,” Fellner requested to join Reinhard von Lohengramm’s forces. His defection was accepted, and Reinhard assigned him to serve under Paul von Oberstein, then a vice admiral and chief of staff. As Oberstein’s assistant, Fellner eventually attained the rank of rear admiral, offering strategic and political counsel to his superior. He remained a close aide to Oberstein during the early years of Kaiser Reinhard’s Goldenlöwe Dynasty.