In the twenty-eighth episode of Joy of Life 2, the one who assassinated Fei Jie was not Wu Zhu, but Liu Zhu. Liu Zhu was the messenger of the Temple. He had the same skills as Wu Zhu and dressed the same way. In order to distinguish them, he was named "Liu Zhu." His goal in coming out of the Temple was to erase the traces Ye Qingmei had left in the world. He had impersonated Wu Zhu to assassinate the people of the Overwatch Council, including Fei Jie. In addition, Fei Jie's heart was on the right side, so he had faked his death in this battle.

The reason Fei Jie was used by the Second Prince was because he had a weakness: Fan Xian. In order to obtain information about Fan Xian, Fei Jie had secretly cooperated with the Second Prince. He did not know that the Second Prince was Fan Xian's enemy. The Second Prince had used this to threaten Fan Xian. The details of how Fei Jie was used by the Second Prince were not mentioned, so there was no way to give a specific answer.
Fei Jie's assassination in the second season of " Celebrating Years " had indeed happened. In the movie, Fei Jie was used by a mysterious assassin with the same weapon as Uncle Wu Zhu, causing the audience to have suspicions. However, according to the plot analysis and the original plot, Fei Jie's death might have been an illusion. His heart was on the right side, so the left side that was stabbed was not fatal. In addition, Fei Jie still played an important role in the follow-up plot, and there were many scenes that needed him to support. Therefore, Fei Jie's death might just be a part of the plot, and his ending might have a satisfactory arrangement.
No, it wasn't. The murderer of the serial murders was the Shadow. He was Sigu Jian's younger brother and also a person by Chen Pingping's side. He had imitated Wu Zhu's crimes in order to assassinate the Qing Emperor. Fei Jie looked as if he had been killed by someone using the same metal rod as Wu Zhu, but it was actually the shadow who had killed him, and Fei Jie had probably faked his death.
In the TV series Joy of Life, Fan Xian's master, Fei Jie, was killed by the Second Prince's men. In the movie, Fei Jie was a ninth-level master who was good at using poison. Before Fan Xian left for Northern Qi, Fei Jie had been poisoned and killed by the Second Prince's people. Later, Fan Xian discovered the poison in Fei Jie's body in Northern Qi. After detoxifying it, he managed to save his life.
Fei Jie didn't die. Fei Jie left the Inspection Institute in Joy of Life and went out to sea with Ye Liuyun to travel the world. After Fan Xian learned that his father, the Qing Emperor, had killed his mother, Ye Qingmei, he and Fan Xian's friends had helped Fan Xian deal with the Qing Emperor. In the end, the Qing Emperor was killed by Fan Xian. Fei Jie left his official position and traveled the world. Therefore, Fei Jie didn't die.
Fei Jie's ending was to leave the Inspection Court and follow Ye Liuyun out to sea to travel the world. After Fan Xian learned that the Qing Emperor was his biological father and killed him, Fei Jie gave up his official position and chose to leave.
Fei Jie's ending was that he left the Inspection Court and went out to sea with Ye Liuyun to travel the world. When Fan Xian learned that the person who had killed his biological mother, Ye Qingmei, was his biological father, the Qing Emperor, all the people around Fan Xian joined forces to help him deal with the Qing Emperor, including Fei Jie. In the end, the Qing Emperor was killed by Fan Xian. Because Chen Pingping had long been killed by the Qing Emperor…
Fei Jie did not die in Joy of Life. He left the Inspection Court and followed Ye Liuyun out to sea to travel the world. In the play, Fei Jie helped Fan Xian deal with the Qing Emperor. In the end, the Qing Emperor was killed by Fan Xian. Fei Jie chose to leave the court and live a peaceful life. Therefore, Fei Jie didn't die.
In the novel " Joy of Life," Fei Jie was the head of the Third Bureau of the Inspection Council and Fan Xian's master. At the end of Fei Jie's life, accompanied by Wu Zhu, he went to Dongyi to find Ye Qingmei's temple.