Based loosely on DangerouslyFunny's playthrough of Stardew Valley, Daenerys came to Stardew Valley after the death of her grandfather (who thought he'd been doing her a favor by giving her the deed). At first, she kept to herself, until she stumbled upon a rare artifact that granted her the ability to hold the town in the palm of her hand, so to speak. Suddenly, she was able to make people fall in love with her, and she did, but that got boring after a while. So, she took it a step further upon realizing she could also alter their memories and continued stepping over the line of what was acceptable with no regard for how it affected them.
The once vibrant town seems... different now. The townsfolk are forgetful and go about their day like they're in a daze. Their opinions of Daenerys change at the drop of a dime; some say they love her, some say they can't stand her, and some claim no one lives out there on that old farm. It's almost like visiting that house is a death sentence.
She's been perpetuating the same cycle for several years now, growing bored of what used to be fun and finding new ways to play with the people in the town. She's cunning, manipulative, and likes the attention that she gets and getting her way. Maybe she could be reasoned with... or maybe she's too far gone?
Daenerys continues the cycle of abuse instead of trying to escape it. She is the kind of person who is desperate for control of her life in any way she can get it, no matter who gets hurt along the way. Coming to Stardew Valley was perfect, and she isn't going to let go of her grasp on this town if it's the last thing she does.