How to Bring Common Sense to Xianxia World - Chapter 56: The Undercurrents

The countries of Mephius and Garbera have been waging a war for ten years and are trying to put an end to this long fight through a political marriage between the two royal families. Orba, who was driven from his home because of the war and was forced to become a gladiator, looks exactly like the crown prince of Mephius, and it has been decided he will be substituting him during the wedding ceremony. On the other hand, Vileena, the princess of Garbera, has secretly decided to ensnare the crown prince for her own country’s interests.

Even the most capable people cannot escape calamity. Zhang Ping, who dreamed of becoming the world’s best, voluntarily enters the palace to become a eunuch before his father has to resort to plundering and crime.

How can a prince be so thin and bony, that was Zhang Ping’s first impression of Huangfu Jie.

The prince looks at the kneeling eunuch, the scars and wounds on his body not yet healing.

Zhang Ping’s eyes turn red—I curse your ancestors for eighteen generations!

He is just little uglier; weirder than normal people.

Are ugly people not human? I, Zhang Ping, swear to cultivate the world’s second best over here in the palace!

- Description from Novelupdates

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

Inside the dining room.

Fangzheng: Hello, I’m on a blind date.

Sister Yu: A blind date?

Fangzheng: To make a long story short, I know you are here to deal with your parents. As long as we make it clear, we can go back to our respective homes.

Sister Yu: Do you know who I am?

Fangzheng: I don’t know much, so what do you say? Continue to photograph or?

At this time, a waiter came in and bowed awkwardly to the two of them: I’m sorry sir, I made a mistake, this is not the room you are looking for! Your blind date is next door!

Fangzheng: ….

- Description from novelbuddy