From Nun to Real Heiress: Expert at Turning the Tables - Chapter 1608

Keiran has always dreamed of being a hero—exploring vast worlds, defeating powerful foes, and growing stronger with every battle.In his favorite RPGs, he could live that fantasy. But when he's suddenly summoned by the god of Eteria, his dream becomes reality.Chosen to stand against the encroaching darkness threatening to consume the world, Keiran is granted four extraordinary abilities: the power to absorb, upgrade, create, and transfer skills.With limitless potential at his fingertips, he embarks on an adventure to collect, refine, and bestow incredible powers upon allies and himself.As he hones his abilities, forging new paths in magic and combat, Keiran will shape Eteria’s fate.From a summoned gamer to a legendary hero, he will not only fight the darkness—he will redefine what it means to be powerful.

The mortal body, metamorphosis, longevity, immortality, and eternal life. These five realms, step by step, reveal themselves in front of you. As a normal person, how can one try step by step to reach and open the door to eternal life?

Between the heaven and the earth lies the mortal body, the mysteries of metamorphosis, freedom of longevity, the power of immortality, and the hope of eternal life. A story filled with endless new magic, a new world of immortal styles, people, demons, gods, fairies, magic, kings and emperors. A world of love and hatred, revenge, and mystical battle, all in “Eternal Life.”

- 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.

Arthur Morgan is an ordinary adult who ended up in the chaotic Marvel universe.He just wanted to be a discreet writer and make money from his books.It also has a 'cheat'.A daily login system.As the name suggests, whenever he logs in once a day he gains something from the system, ranging from skills to completely useless items.…One day, Arthur found a blonde girl passed out at the door of his house.“Why the hell is there a girl passed out on my doorstep!?”