MTL - Waiting For You Online - Chapter 140 .nice to me

The 5,000 years-old boy has resurfaced!In the distant past, young and foolish Asley flunked out of the prestigious Magic University… by failing an early exam that had a 100% passing rate until then. Shortly afterwards, he accidentally created the immortality-granting “Drop of Eternity,” and upon consuming it, obtained an eternally lasting body.He devoted himself to researching magic for almost 5,000 years… after which he traveled in search of the world’s most mysterious Dungeon. Along the way, he happened to save a family, and then their town, from a monster attack. Before he knew it, he was hailed by the locals as a savior with ancient arcane arts and knowledge…While helping to rebuild the town, an opportunity came up for Asley to enter the Magic University once again, so he did. One thing led to another, and his initially normal journey got bigger and bigger — studying, adventuring, monster hunting, money-making, hellish training, uncovering conspiracies, saving the world, the whole nine yards!Thus began the adventure through the mundane and the insane of “Eternal Fool” Asley, his Familiar wolf-dog Pochi, and all their friends and enemies along the way!

When Roland crossed Middle-earth with the Lord of the Rings system, Gandalf was organizing an expedition, the king under the mountain still did not return to his throne, the Hobbit’s adventure had not yet begun, and the world was still shrouded in shadows…

- Description from novelbuddy

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.

She had a lifetime of fake virtue without receiving a virtuous ending. In the next lifetime, she controls fates with the flip of her hand. To the jerk who wasn’t faithful, she’ll draw a premature death talisman for him. For the poisonous step mother, she’ll send a death flower. For the step sister who is two faced, she’ll personally rip off that fake pretty face!

But when she personally offered up her body to her nemesis because of a child who she had no fate with, something unexpected happened. The night of the big wedding, the groom changed and a cold and luxurious man pushed her down. “You can marry whoever you like, but you can only give birth to my children!”

- Description from Novelupdates