Read this excerpt from The Call of the Wild by Jack London.

But Buck did not read the newspapers, and he did not know that Manuel, one of the gardener's helpers, was an undesirable acquaintance. . . .

The Judge was at a meeting of the Raisin Growers' Association, and the boys were busy organizing an athletic club, on the memorable night of Manuel's treachery. No one saw him and Buck go off through the orchard on what Buck imagined was merely a stroll. And with the exception of a solitary man, no one saw them arrive at the little flag station known as College Park. This man talked with Manuel, and money chinked between them.

What is Manuel’s role in this excerpt?

Manuel is the protagonist because he is the main character.
Manuel is the protagonist because he is leading a secret operation.
Manuel is the antagonist because he is altering the protagonist’s fate.
Manuel is the antagonist because he is a violent-tempered man.

answer: C

In narratives, the antagonist or villain can be identified because this is the character that acts against the main character or stops him/her from achieving a certain purpose. In the case of the excerpt presented, it is Manual who acts as a protagonist because his actions affect negatively the fate and life of Buck, who is the main character. This is expressed in "he did not know that Manuel...was an undesirable acquaintance" and "on the memorable night of Manuel's treachery" that show Manuel is evil and will act against Buck affecting his life negatively. Thus, in this excerpt "Manuel is the antagonist because he is altering the protagonist’s fate".