The Immortal Genius Spearman - Chapter 108

Shen Yuan, a normal human who was living his life peacefully on earth died mysteriously, only to get reincarnated into the world of cultivation with an unknown bloodline so powerful that it even surpassed his chest system....“Hmm, looks like becoming an alchemist might be good. System, purchase the Alchemy knowledge.”[Ding!][Congratulations Host, for acquiring Heaven Refining Alchemy Sutra.]...Follow to see the journey of how Shen Yuan creates the strongest harem since the Primordial times to journey the three thousand world.

Lucille was a top student when she suddenly passed away due to a car accident she was transmigrated to the novel that she was reading before her tragic ends, and what's worse she was transmigrated in the body of the Villainess Acantha Solaris who will also die without receiving any love from everyone.

After her previous life, Lan Ke luckily received an universal trade system, and also a ruthless food waster. After initializing the universal trade, becoming a universe merchant, it was the good days of breezing disasters, face-hitting, embracing handsome men! Though as she got stronger and stronger, she stumbled upon the scary secret of the apocalypse!

- 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.