When he was much younger, Wuji was impulsive and impatient. Since then, he has evolved into a cold and calculating personality, often very snide in his remarks. The main aspect about him that keeps him going mentally is his spiritual background as a monk. Having meditated every night since the death of his father, his mind has become clear and sharp - a stark contrast to his muddled thoughts as a child.
Wuji was originally raised as a monk of the Order of Kranekon. From the beginning, he behaved like a rebel. He disliked the teachings and beliefs of the order, and got even more pressure from his peers because he was the son of the monk who possessed the Shadow Sentinel - the near-omniscient spiritual ancestor from the beginning of time.
When Wuji failed to uphold the principles of the order, he was sent away in exile, having dishonored his family. Feeling betrayed, he sought a method to venting out his anger. Thus, he joined the Xeng Insurgency as an assassin. Unbeknownst to him, Grahnato had exiled Wuji to give him a chance to clear his mind, hoping that he would return when he was ready.
Wuji is given numerous targets to eliminate Leir's chain of command in Shuang. Grahnato eventually discovered his actions and revealed his presence when he was in a mission in the Ice Temple. Thus, he is captured by Leirian soldiers who take him to prison pending execution. Having help from the outside, Wuji broke out of prison and became a fugitive. Wuji was then ordered to kill Grahnato, seeing as the monk posed a threat to the liberation of the Xeng Empire. As Grahnato would likely be under heavy guard, Wuji was accompanied by a secondary assassin named Kobushi who would serve as backup.
When Wuji approached his father to assassinate him, he was met with no resistance. Grahnato was open to accept his fate. Wuji could not bring himself to murder his own father, so Kobushi did it for him. Moments later, Kobushi revealed that the real reason why Grahnato was to be murdered was to destroy the supposed "balance" that the order had been keeping between the Leirians and the Xengese. Thus, the Xeng Insurgency begins to raid the Ice Temple to retake the Winter Sigil.
Being regretful, Wuji meditates to ask for guidance, believing that the chaos was his doing. Despite Wuji's actions, Grahnato had faith that Wuji could redeem his honor. Once he did so, Wuji would become ready to received the Shadow Sentinel to become the leader of the Order of Kranekon.
Unfortunately, the conditions of the region of Shuang grew worse and worse, and far more violent. The spirit of Wuji's father instructed him to seek out aid from foreign lands. Thus, he escapes the violence by taming a Spirit Dragon named Seirei who would lead him beyond Xeng territory. He would begin his venture to Oceanfell, where Leir's invasion their had only just begun.