I'm having a hard time deciding which character should be considered the main character (between Joel and Ellie of course). Some would argue Joel, for starters he is the one we play as, and it's his perspective we view the story from. He has a history from both worlds, something that may or may not be looked into. But then we have Ellie, the particularly interesting character who's knowledge of the real world is somewhat distorted. She is the main reason Joel and Ellie are embarking on this Journey and has some kind of importance hence the reason she is wanted by (No spoilers) those outside of the quarrantine zones.
Then there's the idea that the duo of characters should be considered as one, that they are one in the same and hold equal importance as the main role. That makes sense but only if you forget the fact they're both very different from one another.
According to common gaming lore the character you play as is the main character, as it's their perspective you view the world from. Therefore Joel is to be considered the main character.
If Ellie is considered to be the main character, would this mean The Last of Us is the first game to have an NPC as a main character? (To my knowledge at least).
^ The shortest game in history.
IMO, the main character is Joel. Just like in Bio: I, Booker is the one who changes and molds her throughout his experiences and adventures with her. If he never arrived, what would of changed? Same situation with Ellie. Joel and Ellie will both have substantial roles in the game but, I still see Joel as the main character. That's just my take.
Again, I say this not beause Ellie is un-important or anything. She is. She is influential, interesting and all that. But, just like Elizabeth, with the main character they would continue to reside in their prisons (Quarantine/Tower). WIthout the main character's intervening, both girls would be stuck, never freed and not allowed to evolve and grow as characters/people. I hope I'm getting my point across as In just woke up 10 minutes ago.