Why did the faces of Terracotta army and hair look different

They soldiers are handmade, difficult to be the same. Also, it is the reflection of the real life of the people back then, hence different.

they look different as they represent his real army. under his rule, he unified many regions of china and his army was made up of many different people of different races. and his army reflects that...the differences between regions reflected through their facial and hair features.