The usual game design formula says that the final boss is always evil, and Feng Su is no exception. She's so evil she's gone beyond the pale.
The greatest pleasure in gaming is overcoming every obstacle and defeating the boss. Tang Yu carefully made his way through every challenge and defeated the boss, only to find the victory bland and tasteless. He might as well take her home and keep her in secret.
Players: Huh? That's some next-level play!
A serious disclaimer: this isn't an online game. It really isn't!
Theme: An emotional storm