This is just a small theory: Ivankov is indeed correct about Imu, they were originally Nemona Imu and one of the twenty founding kings. However, the rest of the kings were actually genuine in wanting to make a government where all kings and nations were equal, but as he is immortal, once his peers all died off, he used his seemingly Godly power to trick their sons and daughters into making him the sole occupant of the Empty Throne and set them on the path of corruption and decadence into the World Nobles of today.