Rebirth: 100 Days Before Doomsday - Chapter 245: Stand By His Side

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.

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.

Son of the Senior Chancellor, Luo Wei, loved the wrong person in his past life. This mistake caused his entire family to be wiped out, and in the end, he was cast down as a pleasure slave, and died in the wilderness during the depths of winter.

Somehow, the heavens did not give up on him and gave him a second chance at life. He believed this rebirth was only meant for atonement, and not love. Yet, as he plotted his vengeance, Luo Wei quickly realized that passion would again be his fatal downfall.

The once emperor, the lover from his past life, his beloved in this life, and an opposing empire’s monarch who is doomed to love him, who is supposed to be good for whom?

And who is supposed to hurt whom? A hero chasing after a dream, an empire of a thousand years, a kingdom stretching across the known lands, all flashing before the eyes like a mirage. Is it worthwhile to trade a hundred years of my loneliness to give you a single lifetime of joy?

- Description from Novelupdates

This is probably the story of a modern man who became the Seventh son of Kangxi in the Qing Dynasty. This is probably the story of how the Seventh brother Yinyou worked hard and fell in love by the way. So there is no doubt that this article is ambiguous, and it is easy to guess who the couple is.

- Description from Novelupdates