It looks like a section in a textbook. It is suggested that the landlord look at 2. 1, 2. 1. 1, 2. 1.3 first, which may help to understand.

Eptitasis is a concept originated from Horace, an ancient Greek playwright. He divided the tragedy into five parts: overture, protagonist, epitaph, fading period and catastrophe. Later drama theory was simplified into three parts: protagonist, epitaph and catastrophe.

Everyone knows about the disaster.

Protet Sith is interpreted as "the first part of Greek and Roman drama, introducing characters and themes"

The epitaph is interpreted as "the middle part of the drama, and the development of the plot leads to the final catastrophe"

As for how to translate this word, you should ask people who study drama or literary theory.

References:

English Wikipedia, American traditional dictionary