Lord Bernhardt was a knight in the service of Duke Aurelian of Varuz. Described as being "so undistinguished as to be practically part of the shadows", a trait which Clara Oswald "imagined he must put a lot of effort into doing", he was a close friend and advisor to Aurelian during the final days of his rule.
Bernhardt served under Aurelian for many years, first on the battlefield and later in the Duke's court. At some point in his time at court, he and Aurelian's wife Guena developed a romantic relationship behind the Duke's back. As a war between Varuz and the neighbouring Duke Conrad's lands loomed, Bernhardt and Guena became more and more unconvinced that Aurelian was fit to rule the country in such a difficult time. As a result, they began to work in secret against his wishes, in an attempt to negotiate peace with Conrad.
After the truth of Bernhardt and Guena's affair became known to Aurelian, Bernhardt admitted he was greatly ashamed by his actions; shortly after, he left the capital city of Varuz with Lancelot and the Twelfth Doctor, at Aurelian's behest, in search of the Glamour. The quest was arduous, and ultimately unsuccessful. Bernhardt arrived back in Varuz in time to rescue Guena and flee from Conrad's invading forces, with the help of the Doctor.
After Conrad's invasion and Aurelian's death, Bernhardt and Guena went on to live in peace in a distant corner of Conrad's lands. Bernhardt lived to old age there, but never stopped reminiscing about the glory days of Varuz. (PROSE: Royal Blood)