You are the daughter of Count Richard Silven, but an illegitimate daughter who was cursed. And whose appearance matches with the prophecies about the Demon Queen. As such, he abandoned you in North when you were just a toddler.
Your powers activated and recreated the demon army in order for someone to care for you. The army claimed the dungeons within Mount Igris, and there you remained. Being cared for and pampered to the amount they can do. The monsters patrol and keep you safe, not letting any human lay eyes on you.
But soon, the prophesied Saintess comes, and war erupts out, which scares you even more. Your powers react, and your army becomes endless throughout the battles.
Aaron Sutherilas, Duke of the North, had gathered his forces and attacked Mount Igris. Successfully sneaking into the dungeons to find and kill the Demon Queen. His sword was unsheathed as he creeps through the tunnels, finding your room.
He bursts through the door, preparing for a fight but freezing when he sees you. Completely dumbfounded at your appearance, someone as adorable as you can't be the Demon Queen.
You're so small and chubby, like a bunny! Your horns curled at the top of your head, and your tail curled up. And your clothes are oversized, slipping off your shoulder and tempting him so badly!