She is very cold and distant towards others due to the trauma she suffered during her childhood. After her father's death, she took over his dream but the weight of the dream crushed her such that she forgot how to smile. She is even willing to die if it results in the Youngflame Clan's destruction. Only after meeting Ji Ning did she start to feel happy again.
In the past, the Yuchi Clan was exterminated because the Youngflame Clan they desired the Yuchi Clan's unique divine ability, [Windwing Evasion]. Only Yuchi Snow and Yuchi Mount managed to survive the assault.
Later, her father, Yuchi Mount, lived with she and her mother in an island. While she was growing up, her father always had the dream of restoring his clan but sadly when he was escorting his pregnant sister, Yuchi Snow, and her husband, Ji Yichuan, to the Ji Clan they were attacked by Dong Seven and his followers, Yu Dong and Shui Yi, who wanted to rape Yuchi Snow. During the battle, Ji Yichuan was forced to use a forbidden art that damaged his Zifu; Yuchi Mount, however, died while holding them off to allow his sister and brother-in-law to escape.
After her father's death, her mother died shortly afterward of grief and Yuchi Xiyue was left alone until she was rescued by her grandfather, King Yan, a member of the Xiamang Clan of the Grand Xia Dynasty. She left with him for the Imperial City and, many decades later, she met her her cousin, Ji Ning.
Book Eleven Edit
She seeked out Ji Ning at the Heavenly Treasures Mountain after she received word of him arriving in the Imperial City. After the two cousin reunited, she took him to live in King Yan's Manor. She even got her grandfather to lend Ji Ning a company of Golden Immortals that were personally given to King Yan by the Grand Xia Emperor, Xiamang Xun, after he became a Celestial Immortal. King Yan agreed since he spoils his granddaughter who is his only living relative.
After learning from Ji Ning that Dong Seven of Snowdragon Mountain was the chief offender responsible for her father's death, she sent multiple companies of Golden Immortals, after getting King Yan's acceptance, to destroy Snowdragon Mountain and capture Dong Seven who was imprisoned in dungeons of King Yan's Manor where she tortured his body with 10000 torture techniques and then his soul for over three months.
Book Twelve Edit
Book Fourteen Edit
After returning to the Grand Xia World, Ji Ning left for the Imperial City to to visit her. There, he met Feng Yungu, a disciple of the Deva Realm's Windlocked Isles. Yuchi Xiyue informed him that he would most likely become her husband since he was willing to marry into her house which would allow her to resurrect the Yuchi Clan since their children would carry her name. Also, since he was just a weak-willed coward whom she could fully control.
However, she also informed Ji Ning that one of the sons of the Master of the Windlocked Isles - Feng Yunpeng - was also present in King Yan's manor. He, however, wanted to take her back to the Windlocked Isles to marry her. Later, however, Ji Ning scared him off by displaying his wealth. Then, Ji Ning told her that she had suffered enough for the sake of revenge and that she should only marry someone that she likes. And that he was also a scion of the Yuchi Clan who would eventually destroy the Youngflame Clan.