Britannian Imperial Family

Some apparent members of the Britannian Imperial Family

The Holy Empire of Britannia is ruled by the Britannian Imperial Family (皇室, Kōshitsu), descended from Sir Ricardo von Britannia, designated heir and lover of Queen Elizabeth III, which holds the highest positions within its government and military.

Each of member of the Britannian Imperial Family is ranked according to their position in court, which includes the Emperor's consorts as well as his sons and daughters. The ranking of a prince or princess is dependant on primarily on birth order and the rank of the individual's mother. For example, Clovis is the Third Prince while Lelouch is the Eleventh Prince. Lelouch's mother, Marianne, was the Emperor's Fifth Empress. The numbering of the Imperial princes and princesses is sorted by gender; for example, Euphemia is the Third Princess and Clovis is Third Prince.

The princes and princesses use the same nobility particle as their mother, though the usage does not mirror any real-world method. The female members are entitled to elect a personal guardian called a "Knight," who are given authority and placed directly under their command, with their own unit. Cornelia's Knight is Guilford who, along with her, commands a unit of Knightmare Frames. Suzaku Kururugi also served as personal Knight to both Euphemia and Lelouch (as the Emperor of Britannia), donning the title "Knight of Zero" in his service with the latter.

The ranking of the individual is not the sole determination for the order of succession for the throne, which can change depending on the prince or princess's actions or even the whim of the Emperor. Third Prince Clovis has a higher possession in the line of succession than his sister, Third Princess Euphemia, because his mother Gabrielle is higher ranked than Euphemia's mother. In turn, Euphemia's mother held a higher position than Lelouch's mother, Marianne; while Euphemia was younger than Lelouch, her mother's position gave Euphemia a higher position in the line of succession. In contrast, Euphemia's older sister, Second Princess Cornelia, holds a higher position for the throne than Clovis's due her her accomplishments in the battlefield. Sharing the same mother, however highly ranked, also does not necessarily guarantee a higher position for the throne - Lelouch's original position was 17th while his sister Nunnally was 87th in line for the throne.