Juntei (遵帝) was a ruler of Sai from long ago; Enki mentions that he never met Juntei, though the current King of Sou had at one point. His rule had been very stable and he was regarded as a good ruler.
During Juntei's reign, the ruler of the kingdom of Han lost his way, and the citizens of Han were suffering the repercussions. Juntei took pity on the people of Han, and tried to help them by sending part of Sai's royal army into Han, stationing the troops at the border between Sai and Han to protect and help the refugees fleeing the kingdom.
Despite his entirely altruistic motives, Heaven expressed displeasure of the situation - Juntei had directly gone against one of the three Mandates of Heaven that all kings must accept before formally ascending the throne of their kingdoms. Both Juntei and his kirin, Sairin, were suddenly struck dead and the Royal Seal changed from 斎 (Purification) to 采 (Command or Dice) in indication that any transgression where a king defies a mandate of Heaven will not be tolerated, no matter how well-meaning.