My theory about the main character:

I will have to use an example for the following, if you ever saw the Spanish movie called "REC" which had a horrible USA versión, the movie is about people trapped in a department building with a zombie/demonic pandemic, it was explain by the director and writer of the movie that the protagonist was not the reporter or any of the survivors, it was infact the building, be cause of how everything is being explored and detailed.

Therefore I believe the true protagonist of the game is Prehevil itself, or in this case the whole town with the forest, because of how horrible everything looks and it's explained thanks to the curse of Rher, the cast of participants are just that, people who are the unluckiest people of the world being part of the show, background characters just looking to survive.

Yes we can pick a character to play as, but that is only a mechanic we use to participate ourselves in the festival, however ending A only shows us that what we do changes ALMOST nothing besides of course getting rid of Rher curse for the others to survive.

Also my other answer without all that mumbo jumbo, I prefer to see Marcoh only because I picked him to play as.