Emperor of Meiteikoku
Upon the highest spire in Shiho-fushi, capital of the empire known as Meiteikoku, the emperor resides. All of the lands owned by Meiteikoku are ruled over by this person and his advisers. His appearance is as impressive as his status. He rarely leaves his spire, but when he does, everyone knows about it. Dressed in riches from all over the known world, wearing jewelry with the finest gemstones and followed by an regiment of mages protecting him. But even emperors, although being the most powerful people in the world, have to watch out some times. They have to keep their advisers and subjects happy, or assassination lurks around the corner. - Meiteikoku: a guide, A. Essenbau
For one to be considered a candidate, one must have knowledge on a variety of topics (including magic, warfare and economics). Furthermore, one must've done a service to the empire. Non-humans cannot become emperor.
The emperor of Meitekoku is elected by the advisers of the previous emperor, who are in turn members of the three Orders of Magic. The emperor is not allowed to be a member of one of these orders, to preserve the balance of power and avoid bias. The potential candidates are chosen by the previous empire, a list that is renewed every year. The most recent list before his death is the one that the advisers vote on to elect the new emperor.
Looking over the empire, always acting in it's best interest and being an example to it's population are only some of the many duties the emperor holds. In general, Meiteikoku always comes first, before the personal interests of the emperor. This does not mean it always happens, often emperors claim to be a thing they are not.
The emperor is resposible for making sure decisions are made. Some do this themselves, others leave most of it to their advisers. Furthermore, emperors are supposed to attend important ceremonies and lead the troops in case of an attack on the capital, Shiho-fushi.