Cao Cao is a hero. Many people seem to disagree with this.
He continued the life of the Han Dynasty and never proclaimed himself emperor, unlike Liu Bei and Sun Quan, who tied with him. These two men are no more qualified than Cao Cao.
He made great contributions to the unification of the country rather than division. Although China was not truly unified, fortunately, it laid the foundation.
Cao Cao attached great importance to protecting and rebuilding the economy. He institutionalized land reclamation, which effectively improved the productivity and people's living standards in neighboring areas. Zhuge Liang seems to have done the same, but his influence on the whole country can't be compared with him because of the limited conditions in Sichuan. Cao Cao also attached importance to the protection and development of cultural undertakings, and the seven sons of Jian 'an were typical. Perhaps some friends know that it was under his intervention that Cai Wenji was able to return to the Central Plains, and then we were able to see the Tiger Cutting Opera with eighteen beats.
As a politician, he has many means and often conflicts with the morality of ordinary people like me, but that is politics. These means are possessed by every outstanding politician, such as Liu Bei, Sun Quan, Zhuge Liang and so on.
He killed several cities in order to destroy the resistance of the enemy people, which was a very common means at that time. I didn't check whether Liu Bei and Sun Quan were useful, but Cao Cao is not a murderous man, otherwise he wouldn't be an excellent politician.
Details are difficult to find and easy to be confused; But we can see a person's state by looking at the whole story. I am not as good as some friends who really like history, and I can find information in ancient books; I don't know the Three Kingdoms, but I know Cao Cao better. He is a hero.