When The Cute Kunoichis Spied on Their Teacher's Secret - Volume 1, Chapter 6

A god of a different world had abruptly appeared in my classroom and semi-forcibly summoned the entire class to his world.ーーーーexcept for me, Kamiya Yato.

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.

Lukas was forced out of high school before he could undergo the Awakening Process. His dreams of starting a new life by becoming an Awakened were shattered.Becoming an Awakened with supernatural powers meant being bestowed with riches and all the resources needed to fight off the invading hordes of demonic beasts.Lukas received the Slaughter System instead. With every kill, he was able to grow stronger and gain new abilities.[Ding!][Congratulations on Host’s first slaughter.][Current Slaughter Points: 1/500][Host Level: 1][Please Select New Ability]Soon, he was able to fighting off demonic beasts invading and move up the ranks.

Jiang Chengxuan accidentally traveled to the world of cultivating immortals, and accidentally obtained the inheritance of cultivating immortals.

However, the aptitude is really low, and he has been practicing hard for a hundred years, but he still cannot be promoted to the foundation building state.

Just when he was disheartened and silently came to a mortal city, ready to end his life here, Goldfinger finally arrived belatedly.

It is detected that the host has achieved the achievement of cultivating immortals for a hundred years, and I hereby reward one longevity fruit, which can increase one’s lifespan by serving it.

The next achievement task is now posted.

Ask the host to clear the level a hundred times. After completing it, you can achieve the achievement of breaking through the level one hundred times, and you can get one chance to successfully clear the level.

Ding!

Ask the host to complete a hundred times of spell practice, and if you achieve it, you can get a jade talisman for the inheritance of the perfect spell.

Ask the host to complete a hundred times of exercise achievements, which can improve the root bone.

Ask the host to complete the achievement of making talismans a hundred times…

Ask the host to complete a hundred enlightenment achievements…

Ask the host to complete a hundred alchemy achievements…

Ask the host to complete a hundred poisoning achievements…

Please host…

Unknowingly, when Jiang Chengxuan heard the prompt from the system again, he was told that there is no achievement worthy of you to complete, because your existence itself is already an achievement that can never be surpassed.

- Description from novelbuddy