In what way can the Flies by Jean Paul satre considered as an existentialist drama?

"Existence precedes Essence" is one of Sartre's most famous existentialist tenets, and it applies quite well to what we see with Orestes. What it means is that a person exists as a hollow void without any qualities or characteristics provided by nature or a god to speak of; rather, it is only when a person makes a decisive choice to be free and to undertake an action that he or she completely avows to truly begin to exist. Orestes is not defined as an autonomous individual until he decides to embrace his freedom and commit the murder of Aegistheus and Clytemnestra that he knows to be right and just. Man is liberated and defined by action, not a priori assumptions about a human being.