The Princess Was Captured [Western Fantasy]

Bihua is a staunch materialist and atheist. Even after she transmigrates to another world and goes from being Bihua to Princess Bihua, her beliefs never change. At first, Bihua can't even see the most basic particles of magical elements through a crystal. Everyone thinks she's a useless person with zero affinity for the elements. But one day, when the elves, dwarves, and great mages from across the continent are helpless against the demonic flames that burn dragon scales to ash, Bihua strolls straight through them without a scratch. After walking a short distance on her own and realizing everyone else has stopped, Bihua turns around in confusion. "Come on, why isn't everyone moving?" Elves, dwarves, and great mages: ... As the most infamous dark mage on the continent, the Gilbert of legend takes pleasure in massacring cities, consorts with demons, and schemes to let darkness reign over the continent forever. He neither confirms nor denies the rumors, but if anyone actually comes looking for him, he never hesitates to take their life. People curse him, saying that he will be accompanied by loneliness in life and that his soul will sink into the abyss forever after death. Gilbert scoffs at their foolishness. Darkness cannot fall in love. The abyss is his final destination. Later...he eats his words. [I belonged to the darkness, but only you made me yearn for the light.] Romance to plot ratio: probably 6:4. A fruit salad to enjoy before bed. All beliefs are respected. The heroine is immune to magic, but she isn't an overpowered character who slaughters newbies. Theme: Stay positive and love life.