Is that a Wisp? - Chapter 980: Cloud Whale

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.

All the people came to the Chaos Continent, became the lord of one party, and participated in the struggle for hegemony among all ethnic groups.

Tinder is the authority of the human lord. You can sign in on Tinder every day to get population, blueprints, food and other materials.

Huang Yu signed in on the first day and got a discounted artifact.

A batch of discounted products will be refreshed every day for Huang Yu to buy.

then……

“This legendary weapon is only 10,000 magic crystals after the discount? I bought it!”

“0.5% off dragon eggs? Give me 100!”

“0.0…01% off the extraordinary arms training camp! There is such a good thing? Come to the bowl!”

…

Since then, Huang Yu and his territory have become famous in the Chaos Continent!

- Description from novelbuddy

Side story of Kyoukai Senjou no Horizon bundled with the first press release of the 1st, 3rd, 5th and 7th Blu-ray volumes of both seasons of anime.

This side story follows Asama, Kimi and Mitotsudaira aboard Musashi one year before the beginning of the main story, as Asama is considering to create a music band together with her two friends for the next festival in Aki, a territory under the governance of K.P.A. Italia.

The world was consumed by a vile corruption brought from beyond – the sun dimmed, and life as we know it was almost extinguished.And yet it was not the end but merely the beginning.Long after the disaster, a lone survivor awakens with a newfound power to wield the divine flames and many questions about the past. He embarks on a long journey to burn the rot away, discover what's left of the old world and maybe, just maybe, ascend to divinity.