Protagonist and Antagonist

Protagonist
A protagonist is a term used to refer to a figure or figures in literature whose intentions are the primary focus of a story. Classically protagonists are derived from good will, however, this does not always have to be true. Protagonists cannot exist in a story without opposition from a figure or figures called antagonist(s). Classically in literature, characters with good will are unusually the protagonists, however, not all characters who assist the protagonist are required to be simple protagonistic.
In some nineteenth century novels, for example, Wilkie Collins' "No Name," the protagonist, Magdalen Vanstone, is introduced with an extended description, and thereafter simply expresses the qualities given in the description. Similarly, in much "formula fiction", the protagonist will remain essentially unaltered for the duration of the story; no value judgement need be implied by an author's use of either type of protagonist. A refinement can be introduced by an author using the first, evolving, type of protagonist as in Herman Melville's "Bartleby the Scrivener"; though a novel may center on the actions of another character, it is the dynamic character who typically allows the plot to progress in a manner that is conducive to the thesis of the work, and thereby focuses the attention of the audience. The original Greek phrase refers to the central character within a drama, deriving from a conflation of πρωτο-, proto- and agōnistes.
It should be pointed out that the protagonist is not always the hero of the story. Many authors have chosen to unfold a story from the point of view of a character who, while not central to the action of the story, is in a position to comment upon it. However, it is most common for the story to be "about" the protagonist; even if the Main Character's actions are not heroic, they are nonetheless usually vital to the progress of the story. Neither should the protagonist be confused with the narrator; they may be the same, but even a first-person narrator need not be the protagonist, as they may be recalling the event while not living through it as the audience is.
The main character is often faced with a "foil", a character known as the antagonist who most often represents obstacles that the protagonist must overcome. As with protagonists, there may be more than one antagonist in a story. Sometimes, a work will initially highlight a particular character, as though they were the protagonist, and then unexpectedly dispose of that character as a dramatic device. Such a character is called a false protagonist.
When the work contains subplots, these may have different Main Characters from the main plot. In some novels, the book's main character may be impossible to pick out, because the plots do not permit clear identification of one as the main plot, as in Alexander Solzhenitsyn's The First Circle, depicting a variety of characters imprisoned in and living about a gulag camp.
Main Character or Characters
In an ancient Greek drama, the Main Character was the leading actor and as such there could only be one main protagonists, or the chief persons of the drama". This plural use and the use outside of drama attract the disapproval of Fowler in his "Modern English Usage", insisting on the derivation from PROTOS=first. When there is more than one protagonist the story becomes more complex.
Main Character as proponent
The use of 'Main character' in place of 'proponent' has become common in the 20th century and may have been influenced by a misconception that the first syllable of the word represents the prefix pro- rather than proto-, meaning first. For example, usage such as "He was an early protagonist of nuclear power" can be replaced by 'advocate' or 'proponent'.
Main Character in psychodrama
In psychodrama, the "Main Character" is a person who decides to enact some significant aspect of his life, experiences or relationships on stage with the help of the psychodrama director and other group members, taking supplementary roles as auxiliary egos.
Antagonist
An antagonist is a character or group of characters, or, sometimes an institution of a happening who represents the opposition against which the protagonist(s) must contend. In the classic style of story wherein the action consists of a hero fighting a villain, the two can be regarded as protagonist and antagonist, respectively.Contrary to what some people commonly believe, the antagonist is not always the villain, but simply those who oppose the main character.
Writers have also created more complex situations. In some instances, the story is told from the villain's point of view, and any hero trying to stop said villain can be regarded as an antagonist. Such antagonists are usually police officers or other law enforcement officials. In the film K-19: The Widowmaker, an American film about a Soviet Cold War submarine crew, the crew, enemies of the United States, are depicted as protagonists, creating something of a paradox -as very often the American film industry tends to depict the forces of the United States as the people that fight for "good" and "justice", in opposition to them being the antagonists.
More often, stories simply do not have characters that are readily identifiable as most heroic or villainous. Instead, the antagonist becomes that character, group, or metaphysical force which provides the chief obstruction to the protagonist(s) of the story. Note that the antagonist is not necessarily human; often, the forces of nature or psychological elements provide this element of opposition. For example, Final Destination features a metaphysical, though possibly sentient, personification of death which tries to kill people in gruesome "accidents" as part of some large plan.
Srivenkat Bulemoni