Became a Failed Experimental Subject - Chapter 8: It’s Dangerous

The previous lords have committed as many atrocities as possible to fill their bellies. I, the only daughter of that house, had discovered that my servant and lover was a spy.

And as the people wanted, my life ended with my execution.

However, with the memory of getting beheaded intact, I began a new life. I was planning to shoulder the sins of my past life and become a nun, but by some trick of fate, I came to work as a maid for the current lord.

Under my former lover, whose name, age and even hair colour were all lies.

Arthur finds himself reincarnated as a spider in a dungeon after discovering his magical skills in a world of magic and mystery. He knows that everything in this world can evolve into something greater. Arthur begins his journey to evolve himself into a human by conquering one of the most powerful and mysterious dungeons.As he starts his journey, he finds new allies and enemies who look different from him—some who become like brothers and others who may betray him.Finding himself at the center of world politics, Arthur somehow creates his own monstrous kingdom from scratch, determined to live the life he wants and protect the people he loves. In his kingdom, he needs not only power but also strategy, as gods, demons, and other races use their own tactics and powers beyond imagination to maintain control and conquer worlds. Arthur embarks on his journey to live the life he desires... but will he succeed?

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.

Because her appearance was not breathtaking, the Emperor breaks off their engagement and bestows her instead to the bloodthirsty, ruthless, and cold-blooded Second Prince (Wang Ye).

On her wedding night comes endless humiliation, the genuine Princess Consort becoming a deserted women. A foolish woman before rebirth, she no longer expects his love. In this world, she must possess enough talent to awe those around her, carrying herself with composure and articulating with beautiful diction, override above the nine night.

- Description from Novelupdates