Life, Death
The first Duhn Emperor dies of old age and Nagarian and Tigran noblemen look for a successor. A priest claims that the spirit of the Emperor will enter the strongest Tigran or Nagarian if he is chosen through battle. This leads to the first Ascension Rite.
It took the Duhn Empire centuries, but eventually it became a huge force in the south of Zang, powerful in military, due to Naga generals, in culture and unity, since anyone speaking low of the other race would end up in jail or slavery. Speaking bad of the Emperor was heresy and treated even worse than any divisive talk. After the death of the first Emperor in 457, the noble families decided to look for the next possible person to take that position. A priest claimed that his spirit would come to anyone defeating all other competition in duel. So all the noble families sent their strongest warrior to compete in the duel, Naga, Nagarians and Tigrans alike. Of course the next Emperor would be a true Naga due to their physical and magical superiority. From that point on after the death of an Emperor an Ascension Rite is held and anyone from a noble family can enter, but many will die.