The dictator
There are truly only two characters in the poem: the dictator and those who he ruled. According to the poem, the dictator thought that he was a good and just man. However, it quickly becomes clear that he wasn't. He was a brutal, violent, and oppressive man who treated those who he ruled remarkably poorly. He was, in other words, nothing like he claimed to be. The dictator is symbolic of many despots, like Mussolini and Hitler, in the past who have subjugated their people and treated them horribly.
The dictator's subjects
Although never explicitly mentioned, the dictator's subjects are an important character in the poem. The dictator's subjects must endure the dictator's abuses, violence, and other bad behavior if they want to survive. They must indulge the dictator and go along with his every word, even if he is wrong (just like everyone who has lived under a dictatorial regime throughout history). Above all, though, the poem shows that the dictator's subjects had the power to overthrow them if they banded together, something which the poem argues should be done if someone's power grows unchecked for too long.