The System Forces Me to Become the Demon King, but It's the 21st Century

The good news: Lin Yu got her cheat at the age of seventeen, the Strongest Demon King System.

The bad news: She's still in the 21st century and didn't transmigrate to a magical world with the help of good fortune.

[Mission]

[Kill the Dark Crimson Blood Demon that fled the Demon King's Castle]

[Rescue the trapped Shadow Claw]

[Conquer humanity and rescue the trapped Shadow Claw clan]

Looking at a string of missions that were impossible to complete in the 21st century, Lin Yu was undoubtedly in despair.

Things only took a turn when Lin Yu accidentally swatted a mosquito to death.

[Warning: You must not kill the Dark Crimson Blood Demons within the Demon King's Castle at will.]

Oh? Was that mosquito a Dark Crimson Blood Demon?

Lin Yu killed the mosquito she'd driven out of her room with a mosquito coil.

She saved a tabby cat that was nearly tortured to death at a barbecue restaurant.

She reported the restaurant owner for passing off wildcat meat as mutton.

System, is this what it means to be the strongest Demon King?

Isn't this just the Society for the Protection of Small Animals?