Cassius Stirling was king of Wallachia. He was the sole heir of Prince Letholdus Stirling II, who did not live to wear the crown. Due to his young age at the time of King Elric's death, his cousin Nicholas Zuan took advantage and became king in his place. Fearing he would be killed or imprisoned, Cassius fled the castle and lived in the ruins of an Exekian fort for the next fourteen years.
Cassius revealed himself upon Nicholas' death and took the throne, reigning for seventeen years. He married Margot Castile, who bore him three children: Letholdus Stirling III, Odette Stirling, and Stephen Stirling. His rule was largely uneventful, as his role was reduced to that of a figurehead and he was content to let others run things for him.