The Spiteful Bride, Marry to Rival's Son - Chapter 156

Outer Sect Disciple Chen Yu, assimilates within his body a fiendgod heart.

The heart, is the backbone of life, the human body’s fatal vital point. And it can be said that Chen Yu’s heart is actually his strongest defense point, and permits him to overtake demonic beasts, or divine beasts unlimited potential.

Henceforth, he steps onto the stage and surges forth on a magnificent scale, in a heart-rending mysterious journey.

Talented as a cloud, an unparalleled supreme talent.

10,000 races glorious, cross boundary battles.

Only my heart, eternal!

- Description from Novelupdates

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.

He swore that if he was given a second chance to live, he would live his life to the fullest.His life was full of misery but he was reincarnated in the body of the son of the strongest expert in the empire.He had the looks, wealth, and women. He was known as the “Handsome Playboy” and he didn't want to become a righteous protagonist.He awakened a system that can make him strong by making others feel the 7 sins towards him.He will collect many beauties and live to the peak of life.

He was once Head of the Immortal Sects.

Jiang Zheliu resisted the world’s destruction, protecting the people single-handedly. After losing all his spiritual energy, his hair turned white overnight.

All that remained was a millennium passed in vain, and a grave disease.

He distanced himself from the Cultivation World, went to Zhongnan Mountain to collect herbal medicines and grow flowers, as if to retire.

Until….. Those little demons he had once saved, his cherished juniors, even those devils that he had suppressed innumerable times, all came knocking at his door, each more excited than the next gripping his hand:

“Qianbei, what type do you like? Can you not be so rigid on your requirements?”

Jiang Zheliu: “……？？？”

Wenren Ye is newly appointed Devil Lord of the Devil Realm.

He is cold-hearted, devilishly handsome, and when he was younger he suffered a humiliating defeat at the hands of a certain Head of the Immortal Sects.

Still obsessed with this defeat, Wenren Ye hurried through the night to Zhongnan Mountain, but all he saw was white-haired weak Immortal Sects Leader, with droopy eyes, sick to the bone, with freshly coughed up blood staining his lips.

His obsession was still alive, but his heart was also thumping.

- Description from Novelupdates