Not (Just) A Mage Lord Isekai - Chapter 83 - B1 Epilogue

A Russian economics expert had been making money through long-short strategies during the Russia-Ukraine war. Despite his economic success, he felt deep regret about Russia's historical mistakes. He wrote on his blog that “Russia has been on the wrong path since the 19th century,” critically analyzing Russia's history. Then, remarkably, he traveled back in time to 1891 and found himself in the body of Russian Crown Prince Nicholas II during his visit to Japan.

I fell in love. Her name was Shirasaka Yukino. I could only look at her from a distance. However one day I heard that she already had a boyfriend. Even if I love her, I can’t have her. The devil sent me an invitation. I can make her mine!

This is a story of an ordinary boy gaining unusual powers from his nightmares… It all started when Lin Sheng experienced something strange on what he thought was just another normal day. He begins to have recurring dreams that lead him on an incredible journey of discovery as he encounters spine-chilling monsters and elusive secrets.

- 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.