In ancient times, there were always hundreds or even thousands of times more slaves on plantations than white planters. In addition to the plantator's family, the plantation was managed by 2-5 white guards.
How did they deal with the enormous crowd of slaves? All is simple. For different countries and times, the recipe was one.
From the slaves, several dozen guards were recruited, the most outspoken underdogs, who were given an unnecessary bowl of sweets, weapons and the right to beat and kill other slaves impunely.
And these guards devotedly served their masters, and were often more cruel to their fellow men than the masters themselves.
Nothing has changed since then.