Flying Sword is more than a merely-capable swordsman. A genius with the blade and a prominent student of the Illustrious Golden Crane Zin Sun-hai, he has a troubled past from which he seeks to absolve himself.
In his youth, he was a braggart and despite his skill and his school, he treated most of those whom he met as rivals at best and enemies at worst. He would often resort to violence as a first option, and sought to taunt and tempt those he met into provoking him to such.
Through his master, Zin Sun-hai, Flying Sword was encouraged to develop a rivalry with Chu Zhu Ji, prodigious student of his master's twin Lee Sun-tsi. While he initially thought Chu Zhu Ji's skill far below his own, she was able to earn his begrudging respect (if not animosity) for her talents.
As he grew, he grew stronger and his skill was honed by the myriad enemies he made as he traveled. He continued on like this, caught in a downward spiral of dishonor and ultimate self-destruction until he heard of the demon Courage Devouring Shadow.
Such was his arrogance that he sought the demon out and foolishly challenged it. He was quickly crushed, and shown that his ultimate skill and his ego were as nothing before the demon's own power. All things in life which he knew to be true up until that moment were shattered, and his ultimate defeat brought about the balance of his Qi: his over-abundant Yang balanced with his Yin and he was forever changed.
He is uncertain how he escaped annihilation at the hands of Courage Devouring Shadow, and it is a topic he has often explored in thought and calligraphic meditations. Ultimately, he is unsure if he actually survived the fight. For the man who he once was is gone.
Seeking to make right his past misdeeds, he has devoted himself to calligraphy, as it's essence and that of swordsmanship are identical. His first effort was to reconcile with Chu Zhu Ji and the two became steadfast allies, having many subsequent adventures - including forming the Five Tigers of the Borderlands, and defeating Courage Devouring Shadow.
He wields a magnificent relic named "Black Metal Sword" - a very heavy sword with a razor-sharp edge made of nearly indestructible black metal. It was used by the legendary Dugu Quibai, and found by Yang Guo. It requires great amounts of Qi to wield the blade.