Shu XinYi soothed him as he mumbled, "So the entity doesn't exist, but the story is still true." That God or whatever didn't actually exist but the story was still true, because that is the story of this world. In theory, every world's storyline should have a starting and ending point since it does repeat. For a loop to exist, there must be a point where everything starts over, so what decides this point? Well something must, maybe the immediately direct or indirect impact by or towards the protagonist is what could be considered the main storyline.