Thread:Quadstar/@comment-27866698-20151210014117/@comment-27036118-20151210015436

Protagonist is defined as "the leading character, hero, or heroine of a drama or other literary work." The character the player controls is this character: they are the character in which the perspective is focused. Could you argue that Sans and Chara are also protagonists? Definately. But the usage here is because the term "player" is just as, if not more problematic than the word protagonist.

Here's what wikipedia says: The protagonist or main character is a narrative's central or primary personal figure.

In this case, "protagonist" is a substitution for "main character." This character is the person from which this story is seen - it's from their perspective.