MTL - Harry Potter: Hello the Dark Lord - Chapter 9 First heard of "taboo"

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.

“First, a hidden marriage.”“Second, the marriage period is one year.”“Third, you are not allowed to have any feelings for me!”These were his three stipulations to her at the entrance of the Civil Affairs Bureau.She readily agreed and adhered to them one by one.But a year later, is the man holding onto her tightly and refusing to let go still the same cold person from a year ago?“Could you let go, please? Our one-year term is up.”“Wife, the contract you signed is indefinite!”

Three years ago, the animals and plants on Earth underwent crazy and unexplainable changes that included transformations, reversions, and the addition of otherworldly species. And it was the start of a brand-new type of profession in the new generation of humanity – Monster Trainers, people who specialized in taming monsters.

On his 18th birthday, the protagonist of the story, Gao Peng, suddenly received the ability of being able to see the attribute data frame of monsters. With his ability, he aspired to become the strongest monster trainer that ever lived while looking for a method to revive his parents!

- Description from Novelupdates

Dying in a tragic accident Marcus Ferrous gets transferred to a fantasy world of monsters and magic, except when he arrives contrary to what he expected he is now level one and a ghost. Left with nothing on a strange new world, Marcus will struggle with everything he has on his journey to get stronger and uncover the secrets of his new world.