Divine Emperor of Death - Chapter 4461: Fifth Year

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.

Betrayed by his beloved queen.Stabbed by the very men he raised to power.King Alaric died with a broken heart… and a blade in his chest.Fate’s twisted joke?He’s reborn—in chains.Collared. Beaten. Sold like cattle.Once a mighty ruler. Now a slave in a world of magic, monsters, and bastards with crowns.His new master? Arrogant with even little much money, and the personality of a wet cabbage.And the wife?Let’s just say... she deserves better. Much better.Just when he thought a future of licking boots and scrubbing chamber pots—[DING! You have awakened the Domination System.]Rule the strong. Break the proud. Tap the wife. Steal the life.“I—wait, what?”[New Quest: Subjugate your Master's Wife.][Reward: +500 Power | Domination Skill Unlocked – Command Voice][Bonus: Do it on the master’s bed for extra EXP.]He grins through the pain, eyes burning with ambition.They thought they broke him?They just gave him a reason to rise.Power. Revenge. Pleasure.He’ll take it all.------------------Note- No ntr, no yuri.Mc won't abandon his women, neither he will force them, and not every women will be subjugated.And System isn't all about subjugating others wives, it's just one of it's features...

Tao Xiaodong had a blind brother. Tang Suoyan, gentle and calm, was his brother’s favourite doctor. As such, Tao Xiaodong loved Tang Suoyan as well.

Oftentimes, people lose sight of that which was easily gained.

Over the years, Tong Ning was so coddled by Tang Suoyan that he failed to appreciate how fetching this rare specimen was—dumping him without pause, and picking him up again when he had a change of heart.

Except, this time, he was a step too late. Tao Xiaodong had long made his move.

Tao Xiaodong looked at Tong Ning, telling him with a smile, “It doesn’t matter who Tang Suoyan used to be with. He’s mine now. As long as I don’t let go, you’ll never be able to take away what I hold onto.”

- Description from Novelupdates