Chained Hearts: From Slavery to Sovereignty - Chapter 15 - : Wandered in the Mortal World

Once through the pirates, Lu En became the son of Monkey d Dragon, a grandfather named Monkey d Karp, and an unreliable and neurotic younger brother named Luffy.

Fortunately, the ghost back system is activated!

The completion of the ghost back is 10%, and the training effect is increased by 100 times!

The completion of the ghost back is 20%, and the training effect is increased by 1000 times!

…

One day, Lu En, a ghost-backed master, appeared in front of Luffy who was shouting to go to sea, and made Luffy cry on the spot.

Luffy: “The pirates in the sea are all monsters like my brother? I don’t want to go out to sea!”

Garp: “For a long time, the two boys, Long and Luffy, with small arms and calves, I really doubt that they are not my sons and grandsons. Like Lu En, they are the grandsons of the old man!”

Warring States: “The strongest creature in the sea, land and air is Kaido? No, it’s Lu En!”

- Description from novelbuddy

In 2040, The Earth was bathed in powerful radiation when a star went supernova, this radiation granted 50% of humans superhuman abilities but also created a nightmare for them as animals, insects, and carnivorous plants were mutated and became overpowered with intelligence, human started teetering on the brink of survival, a boy with no powers and no father, with a mother in a coma, seems destined for obscurity, but one night changed his life, with a new found hope to cure his mum from the everlasting sleep—Gene Elixir— he went on on a journey that would reshape his destiny...~Voracious Sovereign... Gene Devourer...Pray you won't be devoured by this power you wield which hunger is insatiable~~You call yourself an opportunist... But... you aren't free. A hungry man is not a free man...~

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.

Lioro blankly looked at the game-like screen in front of him.It seems he has traversed to Overlord world with a Yggdrasil like game template![Ding! Congratulations on getting the special profession 'Dimensional Traveler']“......”Can it take me home?------Epic powers check, Epic side characters check, Epic fights check, Epic Romance also check! so what are you waiting for?!?! Read now!ps: it is not a translation but original fanfic.------Worlds I plan to travel to: Danmachi(Ongoing), Demon Slayer(Ongoing), Frozen(Ongoing), Konosuba, Elden RIng, etc.-------Uncomfirmed Love Interests(Doesn't mean they have been wifed, the process is ongoing and is subjected to change under certain circumstances.)1) Hestia.2) Elsa.( yes frozen).