Rufus was the firstborn son of a previous king of the Holy Kingdom of Faerghus, but as he lacked his family's Crest of Blaiddyd, he was passed over in the line of succession. Rufus was given the title of Grand Duke of Itha, while his younger brother, Lambert, inherited the crown instead.
When King Lambert, Queen Consort Patricia, and various other Faerghus nobles were killed in the Tragedy of Duscur in Imperial Year 1176, Grand Duke Rufus assumed regency over the Kingdom since Crown Prince Dimitri was too young to succeed to the throne. During his regency, however, Rufus was quietly dogged by unproven rumors that he had been involved in the assassination of his brother. The Kingdom has declined under his reign, it is rumored that his negligent governance is due to his womanizing.
Rufus continued to serve as regent through 1180, when Dimitri enrolled at Garreg Mach Monastery's Officers Academy to complete his education. He is not close to the Crown Prince and avoids being involved in his nephew's life.
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After the fall of Garreg Mach Monastery and Byleth's disappearance, Rufus is murdered by the Court Mage Cornelia. She then uses this to frame Dimitri for Rufus' death (claiming that he killed his uncle over the rumors about his supposed part in Lambert's death), brand him as a traitor, have him imprisoned and slated for execution for alleged regicide, and then declare Faerghus a vassal state of the Adrestian Empire.