The Beautiful Boss's Personal Bodyguard - Chapter 144

Introduction to One Piece’s Bounty System: Tianlei crossed the One Piece World and become the nephew of the Navy Admiral ‘Sakazuki, ‘Akainu’, Tian Lei thought it was very outrageous until he found himself having a [bounty system] that can be exchanged for everything in the world of One Piece. As long as you kill or capture pirates, you can draw a Skills, weapons, and devil fruits. Such as ‘Navy Six-style’ ‘Overlord color Haki (Busoshoku Haki)’ ‘sense color Haki (Kenbunshoku Haki) ”armed color Haki’ ‘devil fruit’ ‘sword skills’ have everything!

- Description from Novelupdates

Kujo Yuuri, who had been playing Elysia Online, finally changed her occupation to the sage of her desire. Then, she was asked whether to go to the true Elyasia or not and selected [Yes], and somehow went to another world. Furthermore, she became a small child.

The small sage Yuuri and her companions’ love and adventure fantasy.

When he arrived in this world, many familiar stories had yet to begin: Sleeping Beauty had not yet been born, the magic lamp lay buried at the bottom of a treasure vault, Snow White’s father had just remarried, and the Little Mermaid was still playing in the sea with her sisters. In the heart of the desert, the Land of Oz had not yet welcomed the girl named Dorothy.Then he came—the wizard of miracles and wishes.…Many years later, even illiterate children knew his legend: If you find yourself in the darkest abyss or hold the most fervent desire, you might encounter a handsome boy cloaked in robes in a distant forest or lonely mountains.He is the omnipotent wizard, the all-knowing prophet, the sage revered by kings, and the mentor of legendary heroes. He gave Pinocchio life, granted the Little Mermaid an immortal soul, and heard the pleas of both princesses and beggars.Now, it’s your turn.

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.