I Breathe Euro - Chapter 17: Call from Embassy.

In a future city intertwined with science, magic, and various races, a fearsome villain lives.“How dare you try to use such a young child. Do you have no conscience?”“It’s truly regrettable. To think that this girl could be the key to eradicating a den of evil.”“You can rest easy now. We will definitely protect you.”Sorry, but I’m actually that villain…It seems like a serious misunderstanding.

Wang Yi gets a key, opening a door in 2022 will lead to 1982, and opening a door in 1982 will return to 2022.

Two very different great eras appeared before him:

Abundant dietary protection, developed industrial products, miraculous medicines, and explosive information, this is 2022.

Simple folk customs, rich wild resources, scattered antiques, and treasures of the age, this is 1982.

Traveling between these two eras, Wang Yi didn’t think much of it, he just wanted to live a good life.

- Description from novelbuddy

It was only after Su Yayan's death that she realized that she was a malicious cannon fodder female character who became a scapegoat in a Mary Sue story.

This is the story of a modern sailor who was accidentally reborn as a soldier of the Brazilian Expeditionary Force, and finally became the largest plutocratic family in Brazil by virtue of his foresight.

- Description from novelbuddy