Tomodachi no Imouto ga Ore ni Dake Uzai - Volume 4, Chapter 0: Summary

After his fall, the Duke who was distant with his wife and daughter recalled his memories of another world. With a new perspective on life, he swore to cherish and protect those two.

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.

I had to take him home and raise him. There was no bathtub or a large basin at home, so I had to put him in the washing machine for the time being.

It was an hour later before I remembered it again, by which he had been washed extremely clean.

- Description from Novelupdates

After making preparations for transmigration into the VR world “Mystical Era”, the previous veteran player Xia Yuan becomes an NPC, and is even made the fourth son of the Duke of the Empire!Already prepared for a boring aristocratic life, he never expects that the era has totally changed!As the last obstacle, his family has been labelled as a villain by the new aristocracy and will soon be crushed by history! Xia Yuan has no choice but to gradually strengthen his own power according to his knowledge of the game's history.Lost treasures, forbidden ancient weapons, secrets of immortality, forgotten epics...With one's own strength, save the world! Change fate! Rise from the ashes!...The knight swears, the mage sings, and the dragon spreads its wings!Pursue magic and truth, and control the fate of yourself and the era!Stand in the clouds, above the floating city and the throne of the sky!The bell rings, and the signs finally appeared.-It’s time for the stars to align-