Pablo Escobar is one of the main characters. He was a notorious drug lord. Another is the DEA agents, like Steve Murphy, who were involved in the fight against the drug cartels. Also, some of the other drug cartel leaders like the Ochoa brothers were important characters in the real story.
Well, Pablo Escobar is the central character that everyone thinks of. His actions and the power he held dominated the story. But we can't forget about the agents from the DEA. Agents like Javier Pena were deeply involved. And there were also the members of the cartels' inner circles. They were important as they showed how the cartels functioned from the inside. There were also some journalists who were trying to expose the truth about the drug trade, and they can be considered as main characters in the context of the real story as well.