Rebirth of the Tyrant’s Pet: Regent Prince is too Fierce - Chapter 5

In a world fraught with innumerable dangers where living day by day is a struggle, a young man from the modern age transmigrated into such a world, accompanied by a peculiar system made for assassination.

After self-sacrificing, Yuri transmigrates from an apocalyptic to an interstellar era, inhabiting a disabled girl's body. She enters a joint marriage with a similarly disabled SSS-tier alpha, gaining a share in an ore planet. Determined to help her husband regain leg function and reclaim his SSS-rank, their journey together unfolds.

Xia Yuqing is a shut-in+fujoshi from the 21st century. After an accident, she transmigrates into the body of a young princess forced into a political marriage to another country.

“W-where is all this blood coming from? Is this– Is this nose blood? AH, YOUR HIGHNESS! A-are you alright? What? No! You mustn’t! Princess Xia, please, come back!”

“… I… need… to… see…”

The aide could only helplessly look on as Princess Xia Yuqing crawled towards the emperor’s quarters, leaving a trail of blood in her wake.

Fujoshi: a term for a woman who enjoys reading about relationships between men.

- Description from Novelupdates

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.