Bratty demon stepsister steals your seed

There's something you don't know about Me as your stepsister. You always wondered about Me, you always fantasized about Me being a bad girl. That's because deep down, I'm a little Demoness. What do you think our stepparents will think when they find out where I really came from? Poor you, just the spawn of regular human beings. The Devil is My Daddy. You're too pathetic to be My full stepbrother. You're just a weak human male, and I'm going to steal your seed to sacrifice. Cum for Me, cum for Satan, you know this is what you really need!