The second son of Marie Antoinette and King Louis XVI of France, his full name is Louis Charles, Duke of Normandy. He was the last King of France at the end of the Bourbon Dynasty. He was imprisoned during the French Revolution, endured abuse and horrible conditions during his imprisonment, and died at only ten years old. Louis was considered King by French royalists after his father's death, but he never actually ruled, having been in prison the entire time.

In Fate/Requiem:

Karin was one of Louis's kidnapped victims, and one of the few who survived. It was due to this that she and Erice first met.

In Fate/Grand Order:

In the Board Game Apocalypse event, Erice's guilt over killing Louis caused her own Dread Spirits to manifest in the form of Black Marie.