My Cell Prison - Chapter 348 - : Full-scale War

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 magical ring and a mighty spirit inside the ring, coupled with a genius who lost his cultivation and got named worthless trash. That’s Xiao Yan, the poor genius. You think Xiao Yan got it bad? Well, you clearly have not met Jing Yan.

Jing Yan was once the shining star of the whole East City. However, his cultivation dropped because of the Universal Ring that was left to him by his dead grandfather. Without anything but the Universal Ring, he will once more rise towards the top and beyond!

He is Jing Yan, The Universal Sword God.

- Description from Novelupdates

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.

Never touched a girl for five years, living in isolation, and having no skills or idea to talk to a girl.

Tim never thought he would reincarnate in the game he was working on. Now, he had to go through a life that almost seemed impossible for him.

With the Lust System that he created, Tim was forced into a Murim World where strength was everything. And, the only way he could level up was by getting a new girl by his side.

The skills that he could only buy from real currency can only be accessed through quests now.

Can he survive in this world? Can he live with this new life where he has to touch a woman every day of his life? Can he reach the top of the world with his harem?