In truth, it wasn't just Hua Shangnan. Most of the people on the Starship who tried to get close to her had ulterior motives. Even Wang Qing, despite concealing it well, likely harbored intentions that were far from pure.
In reality, Ning Xuan's disguise was quite successful. But no matter how good it was, she was still a woman. Her skin was fine, her build was light, and even with a ghastly scar on her face and her complexion darkened, she couldn't completely conceal her delicate features.
Furthermore, male Spirit Controllers possessed a keen intuition ingrained in their very genes. The higher a male's Level, the more easily he was driven by this intuition to feel an attraction toward her.
Conversely, those of a lower Level were less sensitive in this regard.
