Witch, I'm really not the Deep Sea Ancient God! - Chapter 894 - 490: Battle Whale!

“O, Hero!” With that cliched line, Kazuya Souma found himself summoned to another world and his adventure–-did not begin. After he presents his plan to strengthen the country economically and militarily, the king cedes the throne to him and Souma finds himself saddled with ruling the nation! What’s more, he’s betrothed to the king’s daughter now…?! In order to get the country back on its feet, Souma calls the wise, the talented, and the gifted to his side. Five people gather before the newly crowned Souma. Just what are the many talents and abilities they possess…?! What path will his outlook as a realist take Souma and the people of his country down? A revolutionary transferred-to-another-world administrative fantasy series starts here!

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.

When he stayed at her home and one night, he took her body in a drunken stupor. From then on, he had been a constant fixture in her life. How adamant he was in forcing a marriage was how adamant she demanded for a divorce. “I’m not staying married to you! I’m not staying married to you! I’m not staying married to you!” After she repeated such an important proclamation three times, he finally tossed her the divorce paper. She thought she had finally escaped him alas… After the divorce, he still snuck into her room every night… Finally losing her patience, she yelled, “We are already divorced!” He glanced at her and set down the divorce paper before her. On it, it was written clearly: After the divorce, the car is hers, the house is hers, the company is hers, their child is hers, he… is also hers?

“You saved me, to repay you, I decided to devote myself to you!”An Ran just did a good deed casually, but was entangled by this black-bellied, ice-cold face.“No... no need, I'm still young,” An Ran sweat madly inside, waving her hands repeatedly.The man, however, was very serious: “I will wait for you to grow up.”But, isn't your image of throwing a tantrum too unbearable to watch?Didn't you say you were like Cold-faced Yama, aloof and abstinent, with an eight-thousand-meter glacial demeanor?A certain brotherhood wiped a bitter tear and said, what's the big deal about throwing a tantrum? Neglecting friends for love, betraying friends for affection, and always have to be ready to be fed dog food. They just want to ask, such a brother, can we return him?