MTL - Class Teacher System - Chapter 135 Save the brain

A great demon king who came from another world to conquer Earth. To save the Earth, Li Luyou could only first take care of this great demon king… a little girl proclaiming herself Her Imperial Princess.

- Description from Novelupdates

The aristocratic Lu family has produced a joke, a beautiful one, but a joke nonetheless. The daughter they have been rearing all this while turns out to be an imposter! With the real heiress returning to take her rightful place, everyone is eager to know the outcome of the imposter…Will she be able to survive in poverty after living a life of riches?Having just transmigrated, Huo Yao imagines that this experience will be pretty interesting. However, imagination and reality are always so different!Dad: “Daughter! Take this black card. It has no limit! Use it freely.”Mom: “My dear Yao Yao! If you don’t like this jewelry, I’ll get them to change it immediately.”Huo Yao: “…”Weren’t they supposed to be poor and ordinary? What is with this hidden lavish behavior?Her eldest brother, an investment company’s CEO: “Sis, inherit my company!”Her second brother, a top lawyer: “Whoever dares slander my sis will face the full brunt of the law!”The third brother, an international genius doctor: “Bullying my sister? Should I display the prowess of my scalpel?”Mysterious fourth brother: “My sis is the cutest!”Huo Yao: “…”What happened to being a good-for-nothing person who lives off her parents?A top aristocrat secretly changes into his cheap clothes and drives his crappy old car to her. “Baby, my heart is yours. Why don’t we get married to test if I’m telling the truth or not?”Everyone who knows about it, doesn’t dare say it out loud.All they can do is curse inwardly: “Bah! Keep acting! No one believes it!”

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.

Beings that create and control monsters and demons, beings that build and reign over malicious labyrinths, the chosen individuals to possess an overwhelming Unique Skill… They are the Demon Lords.