Mechanical Alchemist - Chapter 345 - 344: Their Story Ends

The romantic comedy light novel series centers on the gaming lives of various high school students who play video games, including: Keita Amano, a lonely young man who loves video games; Karen Tendō, the beautiful president of the video game club; Chiaki Hoshinomori, who constantly fights with Keita; and Tasuku Uehara, who puts on a facade of being satisfied with his life in the real world, but he in truth loves video games.

Liu Duo was a young girl whose grandmother sold her to four brothers with the intent to be a bride. Unwilling, she ran away the following night, only to fall unconscious while trying to get away. Unexpectedly, however, she was reborn with the spirit of a 25 year old woman, also named Liu Duo.

- Description from Novelupdates

This novel is also known as From The Start, I Traded A Galactic Warship

After getting a trading platform three thousand years later, everything in the world has become an antique, worth a thousand gold.

But it was also learned that three years later, aliens invaded, human beings fell, and the dark starry era began.

In this era of unprecedented change in tens of thousands of years.

Shen Shi decided.

First trade a space battleship, and then talk about it.

then–

Battleships come to the world from outer space! Global shock! Starry Sky Era, open in advance!

- Description from novelbuddy

The young lord of a small and weak country saves a dragon beside the sea one day.