MTL - Control The World - Chapter 527 Self-destruction

This is a world shrouded in darkness, and the pervasive black mist erodes all living beings.

Only fire can dispel the darkness and protect mankind.

But the firewood will eventually run out, the fire will eventually go out, and humanity will eventually perish.

until Rhodes came.

- Description from novelbuddy

Kiyoshiro Takeda lived a life without purpose, drifting through his days with no direction. But one fateful moment changes everything. Now, he finds himself in a world unlike any he has ever known, given a role he never asked for. A new life, an unknown destiny, and a looming catastrophe that only he can prevent. But can someone who failed in his old life truly become the last hope?

Xia Yuqing is a shut-in+fujoshi from the 21st century. After an accident, she transmigrates into the body of a young princess forced into a political marriage to another country.

I returned after 10 years.