Tensei Shitara Slime Datta Ken (WN) - Chapter 326

She, a genius abandoned by her clan. He, a proud, pampered, two-faced imperial crown prince, a developing supreme ruler of the world. She, tricking him, disguised as a pig to eat a tiger, suppressing him, provoking him. Every time, after playing with him and stirring him up, she’d escape.

No man could put up with this! He could only hunt her, pamper and indulge her, lure her into falling in love with him, who would have thought, the one to first fall in love would turn out to be him———-

A young man who stood above the world, a young lady who dominated the landscape, evenly matched opponents, evenly matched romantic game of chase and tag.

- Description from novelupdates

Xiao Rou, a girl growing up in a poor countryside family, finds that she’s actually the daughter of a wealthy couple. Her mother had mistaken another girl for her back at the hospital. Thinking she would change from an ugly duckling to a noble swan and live happily ever after with her real family, reality strikes her in the face.

Diablo Volfir, a mighty magician, was sealed for aeons due to the schemes of the 12 Gods, but 66666 years have passed since then, and he descends to earth once again!

Ruins stretched across the landscape in the apocalypse after the nuclear war.