This is due to history. In the north, Cao Cao held the emperor to make the princes. His ideal is to unify the Central Plains. Have you ever read short songs? Liu Bei, who claims to be a relative of the country, is unwilling to be a straw bag all his life and wants to be the boss; Sun Quan of Dongwu has been dominated by one party, and he is the king at the local level. He is unwilling to obey others, but everyone wants to be the emperor and the boss, so he can only go to war.