Answer:
protagonist and antagonist
Step-by-step explanation:
The two main characters that should be present in a story are the protagonist and antagonist.
The protagonist one of the main characters. The protagonist is the person leading a contest, a principal performer in the story. He/She is an advocate or champion during the course of action.
An antagonist is the other character in the story. An antagonist usually opposes the protagonist in a literary work or drama. He/she is an enemy or opponent who antagonizes or stirs.