Ban Yue was the head priestess of the fallen Banyue Kingdom and claimed as a traitor by its people for allowing the invading army into the city. She appears as a ghost in the second arc of the story. Ban Yue is a very soft-spoken and sullen girl. She is unsociable and rather timid but does not seem to be easily frightened. While she bears no thought for those who hurt her, she remembers the ones who were kind to her for a lifetime. Although initially somber, as the story progresses, she becomes a bit more lively and actively contributes to help out others. Her fighting style is said to be agile and eccentric, yet without any aggression. Despite possessing powerful abilities, she lacks in ability to do everyday tasks like cooking.
Ban Yue was born to a man from Yong'an and a woman from Banyue kingdom. She lived with her family at the border there, but her father soon moved back to Yong'an because he couldn't deal with the fights and tension at the border of the two nations. Her mother never recovered from the divorce and died of heartache not too long after as well. Ban Yue, around six to seven years old at that time, continued to live on the streets. She was bullied by people because of her mixed blood and small stature, causing her to become joyless and gloomy. The Banyue people were cold to her and the only one who was willing to befriend her was a boy from Yong'an who lived at the border. This boy turns out to be Pei Xiu. When she was ten years old, there was an uprising and the armies of the two nations fought a bloody battle that cost many lives. During this riot, she vanished, but since no one in Banyue kingdom cared for her, nobody noticed that she was gone.
Ban Yue crossed the Gobi Desert all alone by walking thousands of miles to Yong'an. There she swore loyalty to the country and continued to be Pei Xiu's subordinate. Once she returned to her home kingdom, she had learned how to control the scorpion snakes and black magic. The people were impressed, but also started to fear her. People who used to make fun of her and feared revenge told the king that she was an evil messenger and was supposed to bring ruin to the kingdom, but they failed to convince him. She later managed to become the State Preceptor of the Banyue kingdom.
One day, another war broke out and the Yong'an nation sent armies to completely annihilate the Banyue kingdom. Ban Yue conducted a grand ceremony to pray and bring blessings upon the soldiers of her kingdom which caused the Banyue soldiers to be thrilled for the battle. At one point however, she opened the fortress gates and let in Yong'an troops under Pei Xiu's command, which gave them the upper hand and caused the Banyue kingdom to fall. Pei Xiu convinced her that doing so would end the war sooner and reduce the number of casualties on both sides. Thus, she was claimed a traitor and soon after, soldiers caught her and hung her up over the Sinner's Pit. Each time she escaped, she would be captured by Kemo and his fellow soldiers and hung up again. During that time, she apprehended all the other kingdom's soldiers and threw them down the Sinner's Pit. She set up an array that only she could disperse, and thus they could never escape. This continued for around 200 years.
