Transmigrating as Qin Er Shi, Building a Multi-Dimensional Immortal Qin Empire

[Transmigration, Qin Dynasty, the Myriad Worlds, conquest] Hu Jing transmigrates to the Qin Dynasty and becomes Hu Hai, the First Emperor's eighteenth son. The First Emperor is on his sixth inspection tour, and Hu Jing learns that Shaqiu lies not far ahead. He understands that he is destined to become the infamous Qin Er Shi. But will events really unfold as they did in history? Hu Jing uses saltpeter to make ice and escorts the First Emperor's body back to the palace at Xianyang. After ascending the throne, he eliminates Zhao Gao, fills vacancies in Qin's official bureaucracy, and wins Zhang Liang and Xiang Yu over to his side. Just as Hu Jing prepares to become a great Taizong who carries the past forward, a portal from the Condor Heroes world appears...

P.S. The first thirty chapters focus on Qin. The first connected world is the Condor Heroes world...