My Mother, King Arthur

Artoria: "Arthur, my proud son, the glory of all Britannia. As the Crown Prince of Camelot, you are destined to inherit everything from me—my throne, all my possessions, including but not limited to the Knights of the Round Table, my Holy Lance and Holy Sword, the noble warhorses in the royal stables, and all the treasures in the treasury."

Mordred: "Mom, Mom, what about me? Oh, I get it! Big brother inherits everything from you, and then I inherit from big brother. That's a happy ending, right? So, Mom, when are you abdicating? How many tables should we have at the wedding? Can I turn your scabbard into a surfboard?"

Artoria: "Knight Mordred, I hereby bestow upon you the title of Earl of Glamorgan. Proceed to your post immediately, without delay!"

Transmigrated to Arthurian Britain, Artorius faces only one question: Grand villainy, or petty mischief?