System Reborn : Don't be a Mary Sue

Every religion has it's paradise, some believe in heaven, some in hell, some in the limbo. However, there is a place above designed for those who created life. For those who designed universes and for those who aimed to create fantasies. This world was called the System arc of Writhers or SAW.
Just as regular life, those selected few would be granted the chance to compete in a ranking system. Those who achieve class SS once they end their journey would be granted the real paradise, as they have payed for their sins.
When alive Piper was a renown author. She died young, beautiful and alone. Living with the principle of no Mary Sue's, no Marty Stues and no convenient romance, she achieved greatness and popularity with each published book she launched.
However, the universe likes to play with people, her mission, give a good plot to bad stories. As who? The one she most despised.