Adding onto this: this was an era where China was all torn up by a massive civil war, so most of the troops were peasant conscripts and ordinary people who signed up because they had no other livelihood. The pre-war Han military was highly-trained and technologically advanced but also small-ish, numbering maybe 20,000 soldiers in the capital and steppe frontier. The provincial governors weren't allowed to raise their own armies for fear of rebellion, until the Yellow Turban Rebellion threw things out of whack. So these nobles were then allowed to raise militia forces, with themselves and a core of professional officers at its centre. But as previously said, most of their troops weren't very good or motivated at all. So battles usually came down to the officers leading a charge into enemy ranks and hacking guys up until their own troops could gather the nerve to follow them into the fight. And because the professionals were the first ones into a fray, there were naturally a lot of duels between the officers from both sides. So while having a single "hero unit" cut down hundreds of grunts is an exaggeration, they were still extremely powerful compared to ordinary soldiers.