Extra's Harem: Invincibility Starts with Marriage and lots of Children - Chapter 39 - Reason for Everything (A Promise?)

“Will you marry me, Anais?” The male lead proposed to me. “What about Selena?” “Selena doesn’t matter. You’re the only one I’m interested in now.” Even without a hint of interest in the female lead. “I’m sorry, but I…” Before I could even utter my refusal, the refreshing sound of coins rang in my ears. [asdf has donated 100 points!] Accept and get ten thousand points “Shall we go pick out a ring first?” Forget about conscience; if it’s fun, that’s all that matters.

Everyone in the City of Jing thinks that bestowment of marriage between Xian Junwang and the daughter of the Yi’an Marquis House is to insert a fresh flower into manure.

Xian Junwang was that fresh flower and the di daughter of Yi’an Marquis House was that manure that was not liked.

It is said that what is heard is false, seeing is believing. Who knows what the truth really is?

- Description from novelupdates

The world ended, seven days of earthquakes, volcanic eruption and then came the meteor storm, bringing something worse—mutation.Now, survivors are group into Shifters, mutated humans and normals.Ava Zhang was supposed to be a Normal. Useless. Disposable.Thrown into a military-controlled bunker, she is sorted into Level Three—the bottom rank, where the weak are left to rot. Starving, overworked, and surrounded by desperate scavengers, she realizes that in this world, strength decides survival.But Ava isn’t as powerless her hidden System activates. The Blueprint System—an ability that lets her design and invent anything, from weapons to high-tech defenses.

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.