Seirei Tsukai no Blade Dance - Volume 13, Prologue

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.

The youngest all-round best actress, Gu Zhi, has traveled through time and ended up in the body of the sweet and naive real heiress she was about to play.Originally, the owner of the body could have soared to new heights after reclaiming her position as the true heiress. However, she stubbornly turned herself into a green tea character hated by the entire internet, ending up alienated from her family with no one to collect her body after her death.On the parenting variety show, her family accompanies the fake heiress on the program but refuses to acknowledge her.Biological mother: I don't have a daughter like you, Yiyi is my daughter.Biological brother: Quit the entertainment industry, make way for Yiyi, and I'll let you come home.Gu Zhi: ...Who cares.I bring my labor-efficient adoptive parents and my adoptive brothers, who are potential stocks in various industries, onto the variety show. Isn't that lovely!!In this way, Gu Zhi and her entire family, who were almost forced out of the entertainment circle by criticism, suddenly became explosively popular.Fan 1: Damn! This woman Gu Zhi has such amazing acting skills! Her singing and dancing are top-notch! She's so skilled at gaming too, is there anything she can't do!!?Fan 2: Sob sob Zhi Zhi, what kind of fairy parents are these, unbelievable. It's another day of being moved to tears by the celestial parent-child relationship.Fan 3: Ahhhh, Zhi Zhi's big brother is so handsome! Second brother, I want to marry him too! Third brother, I could admire that body for a year! I wouldn't mind waiting for the fifth brother either /shy /shyWhen Gu Zhi stood on the industry's most prestigious award stage to receive her well-deserved Best Actress award, her suddenly awakened biological father and brothers blocked her way, asking for forgiveness.However, they were ruthlessly thrown out by the domineering CEO big brother: Zhi Zhi is a member of the Qin family, don't try to impersonate.That evening, the semi-retired Emperor Qi officially announced the female lead of his new movie and specifically tagged Gu Zhi: Sorry, she's already a member of the Qi family.The entire internet: !!!???

Fate and destiny; no one can foreshadow the terrifying challenges on the road to the Pure Land. Instead, one may unearth the evil within the road of light towards paradise.

A King’s Holy Sword, bringing light to the darkness,

An unyielding soul, igniting the fiery hope of the world,

As his soul awakens, the youth fiercely battles the gods of darkness and evil,

As the surging dark clouds gushed out like a phantom, their conflict swept the world like raging tide!

The clash of darkness and light, a massive war on the verge of exploding,

The decisive battle of gods and deities rewrite the creation of the world into one destructive epic!

- Description from Novelupdates

The youngest Wiseman of the continent, Chu Tian, has traveled 30,000 years back in time to the age of antiquity due to an accident.

This is a prosperous era. Rare herbs, minerals, treasure relics and monsters can be easily found throughout the land.

However, this is also an undeveloped era. Communications, traffic, martial arts and technology are in its early stage of development. Prosperous cities lack lighting while its citizens are uneducated.

Our decisive MC using his future knowledge creates Magic powered light bulbs, magic powered telephones, magic powered cannons, magic powered computers, artificial intelligence, psyche internet. 30,000 years worth of knowledge allows him to create miracles and shine brightly in this era. Allowing him to conquer the land and sit firmly on the throne of the 10 realms.

- Description from Novelupdates