He'd already killed most of his enemies during his conquest and unification of China,and did the same when emperor to anyone who displeased him or broke the law. All philosophical schools of thought accept Legalism - which was strictly enforced - were banned.Under Legalism,any infractions of the law were severely punished.Hundreds of scholars were buried alive for owning forbidden books between 213 BC and 210 BC. So,Qin faced little opposition during his reign because those still alive that might have wanted to oppose were either killed or too scared to do so.