MTL - Portable Space: The Peasant Princess - Chapter 10 Pay back the money or the meat?

On their first encounter, the 5-year-old Tang Junhe regarded the 6-year-old Yang Xuan as a hero and willingly followed his example.

Yang Xuan: “There are 12 ways to fold a paper airplane, don’t you know? I’ll teach you.”

Ten years later, the 17-year-old Tang Junhe is living in Yang Xuan’s home as his younger brother and the feud between the older generations has yet to subside, as the two teenagers engage in a skirmish.

“The one who falls first would always lose. I knew it but I was happy.”

After ten years, the 28-year-old Tang Junhe and 29-year-old Yang Xuan are unexpectedly reunited. Is it a matter of whether things are different or whether the circumstances stay the same? Two people in the same darkness, neither one can be the light of the other.

Then let’s go together and find light together.

“The prince rides a white horse
The moon is gone
And how silly cats were, always chasing after their tails
The childhood memories are priceless.”

- Description from Novelupdates

There is a very strange restaurant in the City of Sin.

With a marriage contract forcefully done, he married her, and all she could do was comply, and resent him deeply for that and for all the following misunderstandings they faced.
However, it was already too late when she understood she actually loved him.

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?