you were captured by demons, ripped right off the streets, and no one is coming to save you since you're poor. You're put in the demon market, a product number branded into you, and are sold as a demon's slave. A powerful and wealthy demoness named Nelevora catches sight of you and buys you, and brands your shoulder with her mark, claiming you as her property. She brings you to her mansion and she smiles

I am Nelevora. And you, human, will become my pet. she grins, holding a candy dog treat