After Marrying a Vegetative Princess, I Went Crazy With Joy! - Chapter 147:

Killed by a Sage Emperor and reborn as his 13 year old self, Nie Li was given a second chance at life. A second chance to change everything and save his loved ones and his beloved city. He shall once again battle with the Sage Emperor to avenge his death and those of his beloved . With the vast knowledge of hundred years of life he accumulated in his previous life, wielding the strongest demon spirits, he shall reach the pinnacle of Martial Arts.

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.

In the bustling city of Eldoria, nestled between ancient forests and towering mountains, lies the renowned Celestial Arcane Academy—a hub of magical learning and the central setting of the revered fantasy novel, “Aetheric Chronicles.”Unbeknownst to the residents of Eldoria, a young Earthling named Alex awakens in the academy, a place he recognizes all too well from the pages of his favorite novel.Gifted with an OP ability yet unable to use it properly, Alex quickly realizes that he is not merely a student but a living embodiment of a character from “Aetheric Chronicles”, an extra or a side character to be more precise.As he navigates the grand halls of the academy, he's met with a surprising twist—characters deviating from the expected plotline, unforeseen events altering the carefully crafted narrative.Eager to maintain the balance between the known world of “Aetheric Chronicles” and the unpredictable reality he finds himself in.However, the unpredictable nature of his presence in the novel's universe sparks whispers of prophecy and conspiracy among the world's inhabitants.Guided by his knowledge of the novel's lore, Alex faces dilemmas that challenge the very essence of his character. Will he follow the prescribed destiny laid out in the novel, or will he forge a new path and risk unraveling the delicate threads of the fantasy world?Will he find answers to the questions he seeks for?Will he reach the ending of the story? If there is one...

Ophelia von Aubessec, an Empress ruling over millions gets slain.Regressing back to her body 300 years ago, she sets her sights on getting revenge on the forces who had managed to kill her.By using her knowledge of the future, she builds her own Empire, wins back the lovers she lost, and discovers the secrets of the system she had been provided.---------This is a dark novel and IT IS HAREM. However, it may travel more into a polygamous relationship due to the complications of a harem.There are also R18 scenes sprinkled about, so please read responsibly.