I Can Turn into a Fish - Chapter 221 - The Sunken Submarine

“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.

“It’s finally here,” said the man with the sword in an echoing whisper.

“The Tower of Choice, the last 100 floors!” the band of five exclaimed in unison.

Angelica came down from the altar with a dull look, seemingly annoying.

Then we looked around.

“I tell you once again, but you’ve had a lot of trouble in the meantime. I couldn’t have climbed to the 100th floor alone without you.”

Thud!

One by one, they fall to the floor.

Angelica’s dagger pierced my neck, and I felt a darkening in front of my eyes with a tumultuous rage. My awareness faded, from my senses, from everything else. After that, everything was eroded by profound darkness.

〔Congratulations, for mating with a Queen Bee you got a new achievement: ”Not a virgin”! Your reward: “Drone Consort” title.〕‘Hey! I wasn’t a virgin before this, system!’Imagine that you lived a painfully average life, died by a stupid, stupid accident, but a goddess interfered and gave you a second chance in another world.There, you became a consort of a beautiful, big-chested queen, and your only job is to have mind-blowing sex with her so she could have thousands of your adorable daughters. In return, you can live in peace and luxury for the rest of your days.Which means, for about two months. Because I’m a bee. And my queen is also a bee. And bees don’t live for long.The only way to increase my lifespan is to develop my bee colony. A hard task in this huge world filled with dangerous and hungry beasts, other war-hungry insect tribes, and natural disasters.But I have a hundred thousand daughters, some actual brains, and with superior genes given to me by my system, we will be unstoppable!===Note: no NTR, harem, incest, or outright smut.