Why did Nebula kill Shangguan?

In the face of Bago's and Bal's yang conspiracy, Li Nebula had no choice at all, he could not dissolve the snake venom himself, and if he allowed these bad guys to survive, then all the reputation of the bad guys for the past 300 years would be destroyed, and the people of Taiyuan would lose their lives as a result. Therefore after getting a reply from Shangguan and the others, Li Xingyun did not hesitate to make his move.

Li Nebula will only show some reluctant smile when facing Ji Ru Xue, only Ji Ru Xue and the others know how many sins Li Nebula has undertaken, with the Shangguan's exit, the world understands Li Nebula has one less person.

Painting Jianghu (also known as Legend of Nebula) is a national animation series. It tells the story of the main character, Li Nebula, and his companions' constant struggle against various forces in the chaotic world of the late Tang Dynasty. It premiered on July 31, 2014, produced by Beijing Ruosen Digital Technology Co.