Becoming evil makes you ten times stronger, but becoming a demon gives you hundredfold strength - Chapter 48 - 41 My Proposal

A girl Alicia lived as an orphan in a world of sword and magic Ciel.

One day, she learned that she was an “otome game’s heroine”. Even her parents’ death was simply a part of the scenario. Alicia judged the heroine’s setting as 「nonsense」and discarded it decisively. She introduced herself as adventurer 『Aria』, gradually mastered multiple weapons and magic, and grew to become the 「Ash Crowned Princess of Slaughter」! But, by accepting a request to guard the “villainess”, before she realized it she got dragged into the stage where nobles quarreled against each other――？

「I am “I”. I’m not a game character!」

Create weapon! Train your body!

Survive the fighting against powerful enemies and smash apart the otome game!

A sublime and exhilarating other world battle fantasy with charming fighting heroine!

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.

Xiang Xiaoyuan transmigrated to a book with a male lead, becoming the male lead’s stepmother.

However, being seventeen and in the middle of his adolescent phase, the male lead virtually ignored his stepmother, and while his father was thirty-nine and a gorgeous man carrying maturity and elegance, he was enigmatic, with no one capable of knowing what he’s thinking.

Xiang Xiaoyuan: The first rule of transmigration, value your life and stay away from the male lead! Being self-conscious, Xiang Xiaoyuan decided to focus on making money, and her business was booming… but before her hopes to get rich were fulfilled, she somehow dealt with her husband and stepson?

The male lead said gingerly, “I won’t think of you as my real mother, but don’t worry—I’ll be a good son and you won’t live out your final years tragically.

Xiang Xiaoyuan: “…Thanks.”

Some other day, her husband stood at the doorway, stopping her and growling, “I heard about something you mentioned outside, that men only care more when they’re older? So? Are you complaining that I’m old now?”

Xiang Xiaoyuan said, “…Wait, listen to me!”

Lu Wanggui was a cold person, which led to her ex-wife divorcing him, and he was not particularly close to his son. Later, to give his son a ‘home’ and to avoid his parent’s ramblings, he married another wife—a docile, dutiful wife.

But unbeknownst to him, that docile, dutiful wife had changed, and she even had the guts to scold him now. Pursing his lips in displeasure, Lu Wanggui was about to remind her of their prenuptial agreement when his son suddenly popped up to defend her!

Lu Wanggui: “???”

What’s going on? Weren’t things cold between these two?

The son: “Ahem. Father, Stepmother… isn’t that bad.”

“Is this man not going to divorce me? Why does he still ask me to warm the bed every night?”

A certain man said this was due to the winter being too cold. However, when summer finally arrived, she still needed to warm the bed, thus a certain girl could not take it anymore:

“I want a divorce!”

A certain man only smiled wantonly and said, “Divorce? Sure, as long as you agree to two conditions of mine.”

“What conditions?”

“Either you pamper me or I pamper you, the duration is ten thousand years…..”

- Description from Novelupdates