Aub Ehrenfest

The Lord of Ehrenfest governs the duchy of Ehrenfest, where the events of the story take place. The current Lord Ehrenfest is Sylvester.

History
Hundreds of years ago, the territory was conquered by a neighboring lord. The noble with the largest mana was chosen as the new lord and named the territory Ehrenfest and became the first Lord Ehrenfest.

From there on, the archduke is chosen from the children between the archduke and his first wife. The child with the most mana, and preferably being male, becomes the next archduke.