Doctor and His Glamorous Sister-in-Law - Chapter 639 - 642 They’ve All Arrived

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.

All the experts were defeated, I want both beauty and wealth! The Dragon King returns to the city, bringing an end to peace! This is the legendary tale of a cultivation fiend.

The doomsday fell upon the earth when a dragon coffin sealed under a snow mountain for ages shifted, and the civilization of gods and devils began. The whole universe turned into a fantastic new world where everyone could rise to the top through cultivation. A lucky young boy seized the opportunity, and started his journey to be an overlord in cultivation.

- Description from Novelupdates

Long Fei, a cross-timer and doujin, is an otaku who traveled to another world. In the original world, he was an otaku fan of Gundam and military science fiction.

He died in an accident and was reincarnated into another world. The Gundam works he had read before his death and the techniques in various military novels could be brought to another world.

How would he use the Gundam that Long Fei created? What waves can be caused in this different world?

- Description from novelbuddy