Most of the 24 heroes of Lingyange were founding generals, who made great contributions to the establishment of political power in Li Shimin. As for Yu Shinan, he has never been on the battlefield with Li Shimin, but his ranking among the 24 heroes shows how much Li Shimin trusts him. Yu Shinan used to work for Dou Jiande, but Li Shimin was more talented. Finally, Yu Shinan surrendered to Li Shimin, so he met his own Bole.
Yu Shinan is a scholar who worships Confucian classics, which is also deeply loved by Li Shimin. Li Shimin has always been the solid backing for Yu Shinan to carry forward Confucianism. The two can be said to support each other in this respect. Not only that, Yu Shinan practiced calligraphy very well, and Li Shimin especially liked calligraphy literature, so their communication deepened and their relationship was gradually established in calligraphy.
However, due to Li Shimin's love for himself, Yu Shinan did not forget his duty as a loyal minister. Politically, he always reminds Li Shimin not to make mistakes. After Tang Gaozu's death, Li Shimin wanted to rebury Tang Gaozu and built a huge grave for him, but Yu Shinan dissuaded him. Li Shimin also knew that people could not be resurrected after death. Yu Shinan's existence can always alert himself, so Yu Shinan's existence in Li Shimin is like a mirror, which is also one of the protagonists in Lingyange.