Blackstone Code - Chapter 3:

Su Shuilian was the first legitimate daughter of a renowned embroidery family, but she was murdered by her jealous family member. After death, Su Shuilian’s soul enters an unknown female body who lives in a dynasty she had never heard of.

While trapped in the wilderness with her wolf pup companions, Shuilian picks up an assassin who was betrayed by his organization and saves him from the brink of death.

After making it out of the dangerous forest, the two travel to a small town with few inhabitants. There, they find a location with a picturesque scenery and disguise themselves as a married couple to buy a house to settle down in.

She was a girl unfamiliar to this world, and he was an infamous assassin. Journey with them as they adapt to their new life…

- 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.

Ronan was just another overworked office drone until a sudden death transported him to a vast, unfamiliar fantasy world—alone, invincible, and armed with absurdly powerful abilities from a game he once played. But reality isn't as simple as a game, and after days of wandering the unending Nim Forest without finding civilization, his optimism begins to fade.Just as isolation threatens to wear him down, he encounters Frieren, a quiet elf girl hiding in the bushes. Their meeting marks the first step on a path neither of them fully understands, in a world that seems empty, yet full of mystery.

An unexpected journey took a group of university students into a secret room from which, upon returning, they began to disappear one by one. In order to unravel the mystery, they joined forces, traversing heaven and earth, diving deep into seas, crossing the farthest corners of the world, and even daring to time travel, only to find that behind each puzzle lay yet another.