I Have Ascended the Throne, Why Did My Father Rebel?

Traveled to another world and became the second son of Emperor Qianyuan of the Daqian Dynasty. As the second prince who is not good at anything and is not favored by the world. Jiang Cheng wanted to just lie down, but he didn't expect that the late emperor had to feign death and stay in seclusion for three years in order to practice his ancestor's secret method. In order to regain the throne after leaving seclusion, he deliberately passed the throne to him who was the most useless. Fortunately, the strongest emperor system is activated. Summon the Soldier Immortal Han Xin and obtain the soldier type: Soldier Immortal Army. Summon the famous general Yue Fei and get the unit: Beiwei Army. Summoning the Conspirator Kong Ming... A distinguished figure in Chinese history came to vote on his own initiative. Three years later, the late emperor returned and wanted to seize the throne. Jiang Cheng has countless advisers and famous generals behind him. "I have ascended the throne, why did the late emperor rebel?"