Yu Xuan is an exceptional Chinese Flame Haze who is bound to the Crimson Lord, Di Hong. She has the title "Wielder of Blooming Sword" and is known as one of the best Flame Haze in the East. She is also an acquaintance of Sophie Sawallisch and Wilhelmina Carmel. Her name is greatly feared by those who come from the Crimson Realm, even Sydonay, who has known her for thousands of years, still has difficulty fighting her without his personal spear, Shintetsu Nyoi. (Source: Shakugan Wikia)