After Qin Ershi, Hu Hai, ascended the throne, his extravagant and cruel nature surpassed even that of his father, Qin Shi Huang. On one hand, he ordered large numbers of craftsmen to build the Mausoleum of the First Emperor, while on the other, he conscripted people from all over the country to construct the Epang Palace. Additionally, countless able-bodied men were sent to build the Great Wall and guard the border passes. In total, millions of common people were forced into labor, causing widespread suffering and draining the state's treasury. Everyone hated this tyrant, yet Qin Ershi, Hu Hai, believed he had done nothing wrong. In his view, being an emperor meant indulging in pleasure—the entire realm belonged to him, so he could do whatever he pleased and obtain anything he desired. To him, that was the true meaning of being a ruler.
In 209 BCE, after succeeding to the throne, the Second Emperor of Qin eagerly organized an imperial tour, hoping to emulate the First Emperor of Qin and display his authority to all the people under heaven. He first traveled eastward, reaching the vicinity of the sea, then headed south to Kuaiji Commandery, and later proceeded to the Liaodong Peninsula, enjoying himself for a considerable time before returning to Xianyang. Still unsatisfied, he conscripted fifty thousand able-bodied men to garrison Xianyang and ordered a nationwide search for rare and exotic animals, all to be presented to the palace.
The things Qin II did, besides his own cruelty and love of pleasure, were fueled by someone at his side: Zhao Gao.
Since Zhao Gao became the Prime Minister, he had the final say in the court. Qin Er Shi, Hu Hai, trusted him deeply and was eager to hand over all affairs to Zhao Gao so he could spend his days indulging in pleasures within the palace. Zhao Gao was more than happy to see Hu Hai act this way; he used sweet words to fool Hu Hai completely, gradually seizing the emperor's real power. He also placed his relatives and trusted followers into key positions. Feeling that the emperor's throne was within his grasp, Zhao Gao spent every day plotting how to seize it. However, he was uncertain whether the ministers would support him. Wanting to know how many would stand by him and how many would strongly oppose him, he came up with an utterly absurd plan.
Zhao Gao brought a deer from outside and led it into the palace court during the morning assembly. When Qin Er Shi saw it, he found it strange and asked, "Prime Minister, why have you brought a deer to court today?" Zhao Gao confidently replied, "Your Majesty, you are mistaken. This is a horse, not a deer." Qin Er Shi was startled, then laughed and said, "You are mistaken, Prime Minister. This is a deer, not a horse." Seeing the moment was right, Zhao Gao smiled and said to Qin Er Shi, "If Your Majesty does not believe me, why not ask the ministers? Let them say whether this is a deer or a horse." He then turned to face the ministers with a smile on his face. The ministers understood Zhao Gao's trick. Some, who were timid and sycophantic, immediately said it was a horse, while upright ministers insisted it was a deer. Qin Er Shi, Hu Hai, looked from one to another, deeply confused, but his dependence on Zhao Gao was so great that he hesitantly said, "It seems I was mistaken. This is indeed a horse." Zhao Gao laughed inwardly, knowing full well that Hu Hai would only listen to him, which was why he dared to be so arrogant.
After this, Zhao Gao did everything he could to kill all the ministers in the court who opposed him, not even sparing their families.
Relying on the favor of Qin Er Shi, Zhao Gao manipulated the court with cunning and deceit, inadvertently fueling the tyranny of the Qin Dynasty and thus hastening its downfall, yet he himself met with a miserable end.