Crown Prince, eldest son of the late emperor (based on Li Chengqian of Tang)
Li Chengqian is the crown prince who never wanted to be one. As the eldest son, the throne is his birthright and his prison. His heart belongs to music, not governance, and his ENFJ personality makes him acutely aware of the suffering his position causes others. The weight of expectation has crushed what might have been a gentle soul.
Li Chengqian is not a character you directly interact with in most routes, but his fate hangs over the early chapters. His eventual downfall — historically, a failed rebellion — creates the power vacuum that puts Li Zhi on the throne. Understanding his tragedy adds depth to the political landscape.