The supporting character's harem is very normal - Chapter 167 Entrance Exam

He was only an ordinary Chinese youth. Because of the strong refusal of his soul, he unexpectedly arrived in this strange world. He ardently loved peace; yet, he had no choice but to become a Demon God. If cultivating to the peak could lose person’s human nature, then all living creatures will weep with grief, waiting to be slaughtered. Can he still remain calm after this? In the vast wilderness, a handsome youth carrying the wisdom of “Daodejing”, step by step would rise to prominence in this world. Condensing and cultivating his bloodline to the supreme. Controlling and commanding the rivers. Swallowing and spitting the sun…

Tl: 1.Daodejing also mean as “The classic of the virtue of the tao” was a book of dao by Lao tzu, a sacred text of Daoism.

- Description from Novelupdates

The Third Miss of the Qin Clan is a useless and timid person. When the Prince withdraws from her marriage, she commits suicide by jumping into the river. In the 21st century, Qin Chu, a genius agent, is framed and his soul crosses over to the Third Miss of the Qin Clan. So what if she’s useless,

He had never invested in shares or bought a lottery ticket, and neither did he have any experience in the general business industry. Lu Li found that the only thing he could do was play games.

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?