This Witch Transmigrated into the Romantic Novel's Supporting Role - Chapter 13: Add wechat

Su Wan is a Realm Destroyer. She shuttles to different time-spaces using the identity of the “Cannon Fodder Ex-Girlfriend”, dedicated to plotting how to happily tear apart the male protagonist and the female protagonist. –There’s no such thing as protagonists who can’t be torn apart, only Ex-Girlfriends who don’t work hard enough~

- Description from Novelupdates

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.

“I beg you, please teach me how to pick up female angels!!!”
Pleaded the twelve-winged angel.

“Teacher!! How can I fool more people into my sect?”
Asked a devil in the devil world.

“Do you know how to save the family cat that died last night?”
Someone in the sky is too embarrassed and asks me quietly.

“All the angel, all the big deity, please I am not God, I am really just a summoner….”
I said painfully.

This is the story of a poor boy and how he becomes the greatest summoner who dominates the six worlds because of an accidental acquisition of Dimension.

- Description from Novelupdates

In this brutal world ruled by the law of the jungle, Ximen Wei is driven by his desire to return home and escape his past regrets and feuds.

As he becomes increasingly obsessed with achieving his goal, he loses his emotions and humanity, resorting to any means necessary, no matter how unscrupulous or immoral.

He becomes a symbol of massacre and death, a demon god feared throughout the Qi World for his willingness to kill anyone who stands in his way or possesses something he needs.

Follow Ximen Wei's journey as he rises to power, terrorizing those around him in his quest to become a powerful demon god.