Rakuin no Monshou - Volume 5, Afterword

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.

A sweet yet difficult journey to get his ex-wife back.

She had a marriage contract with him. Her father forced him to marry her because she loved him so deeply. However, he didn’t love her and asked her to sign an agreement, according to which they should split the cost of living, have no children and get divorce four year later. She accepted all conditions because she thought that she was able to melt his heart.

However, after three years, nothing changed. He was still as cold as ice. At that time, another woman appeared. She was his co-worker, and she called him “Brother Chen”. Lu Yao gradually discovered that their relationship seemed to be vague.

What was worse, she was unexpectedly pregnant, and she wanted to give birth to their children. As she believed that he would definitely make her have an abortion, she told him that she was going to divorce him.

To her surprise, he refused to leave her and started to treat her with passion like he never did before. He hounded her nearly every day. It seemed that he realized the importance of her only after he was about to lose her.

And he found that she was so charming when she no longer pleased him and started to live her own life.

Eastern Jin’s Regent had icy, jade-like beauty and peerless talent. It was said that his admirers were enough to fill 3 entire cities!

Eastern Jin’s Regent was only second to the Emperor and temperamental, but rumors are that a young fox entered his bathroom, yet actually didn’t die. Eastern Jin’s Regent known for being mysophobic, never touching any females, but he only loved the fox. He even held the fox as he slept!

You fake god! I’m a human, ah! Turning me into a fox and transmigrating only to let some guy take liberties with me every day? Fine! Since its like that, I’ll eat from him, drink from him, use what’s his, play him, and bed him…

- Description from Novelupdates