Who is the antagonist in The Trial and Death of Socrates: Four Dialogues by Plato?

This collection of conversations between classical Greek philosopher Socrates and those who question and/or challenge him is one of the earliest, and most significant, works of philosophy in history. Written by Plato, a pupil of Socrates and a noted philosopher in his own right, the four dialogues in this collection take place over a period of time from the beginnings of Socrates' trial in Athens to the day of his execution, and explore themes relating to the nature of existence, the nature of death, and the value of wisdom. There isn't an antagonist in afictional sense.