The Dawn Typhus based Zelda RP was supposed to be an adaptation of Shin Megami Tensei III: Nocturne with Dawn Typhus in the role of Demi-Fiend, and a young boy in a wheel chair named Damien (who is really Demise from Skyward Sword) taking the role of Lucifer. It was supposed to take place on Hyrule. Dawn was supposed to be an unconnected nobody to any of the prior Hyrulean stories. A mother, father, and brother Derek were brought in to solve one problem: Mary Sue-isms.
The Zelda OC landscape is a trash heap of Secret Princes and Princesses, Clone characters, evil twins, or 'Dark' aspects. I wanted to stay as far away from that as I could. Dawn worked out pretty well for that role. In this story, it is Vaati that implants her with the symbiote that makes her half Demon, giving her the demon markings all over her body.
The basis of the RP was that Dawn could cast a deciding vote via her actions twoards a multiple ending setup. Dawn's actions could steer Hyrule in a 'Law' or 'Neutral' or 'Chaos' direction.
Link was Hyrule's 'Satan' in Shin Megami Tensei terms. The highest enforcement of law. A Dawn that agreed with Link would learn more law. A Chaos Dawn would result in Dawn going down the Proverbial 'Road to Hell' where Dawn would meet and agree to join forces with Damien. The problem became that I have experience mostly with "Ganon Timeline" games. In addition, the SMT III based aspects didn't make all the sense in the world.