My Goddess is Good at Pretending - Chapter 759: The Fallen Sovereign

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.

They had been together since high school. Together, they faced the cold faces of their parents and the satirical or disdainful eyes of others, started a business and experienced all kinds of ups and downs. When their company was on the right track, Zhishu He was asked to give up his career to stay at home, while Wenxu Jiang gradually changed and began to indulge in merry-making. However, Zhishu chose to forgive him. Zhishu got an incurable disease, while Wenxu Jiang was still indifferent. Zhishu still chose to forgive him. Love had become a kind of habit, which was equal to an incurable disease.

In a peaceful sunny day, Zhishu quietly left Wenxu Jiang and the house in which they had lived for a long time without an advance notice.

Soon he was gone. A man with pure spirit and deep love for Wenxu Jiang disappeared from this world forever…

Sometimes love cannot stand the test of time. Someone will not know how to cherish the love until he loses it…

- Description from Novelupdates

Transmigrating into a fantasy world, starting as a typical rich and handsome guy, he has a useless main character fiancé, a sister who knows the future plot, and a distant cousin who is the reincarnation of his nemesis, the Nine Heavens Mysterious Maiden.He becomes the final boss in a female-oriented novel, forcibly killed by the plot?Although he has a system that allows him to become stronger by binding with geniuses, Jiang Minghan states that as a gentleman who likes to stay calm and friendly, he just wants to be good to others and doesn’t want to be a villain.To avoid the fate of being overpowered by the female leads in the future, he can only walk further down the path of a villain.But unknowingly, when did he become the source of darkness, disrupting the eternal heavens?

The dungeons appeared 3,000 years ago. New wealth and ways to gain power poured into the world, tipping the world’s power balance.

People rejoiced in their appearance. Now the poor could thrive, escaping poverty.

There were countless people trying to enter the dungeons. They formed a guild to manage them. We named them the Explorer’s guild.

All who ventured into those dark, evil places given a title to signify their status.

[Dungeon Scout]

A special occupation created to control the people who entered the dungeon.

A young orphan, adopted by dungeon knights and, would eventually follow in their footsteps.

His name was Vincent Schwartz, born in a fractured world of death and decay.

On the day of his 18th birthday, when children could ingest a special fluid and awaken.

Vincent awakened the unique [Summoner] class.

Able to summon distant beings that wielded endless power, able to perform terrifying attacks.

The only problem was the strange system, which appeared out of nowhere.

[The Demonic Choice System]

This system would give him random choices and give different rewards at different intervals in his life.

Would his system help him attain a wonderful life, filled with women he loves?

Perhaps the world will force him to fight, as the dungeon’s purpose remained hidden in shadows.