The Villianess story: A 100 ways to kill your husband - Chapter 54: Enemy of the Enemy

Officer, if I told you this just was a “Healing-type Game,” would you believe me?

A surgeon accidentally got the blessings of a system, shocked the medical industry, and rejuvenated countless people.

- Description from Novelupdates

In the chaotic world of Ancient Greece, a modern soul is reborn into the body of a young warrior. Armed with knowledge of future empires, military tactics, and innovations, he has no mercy for his enemies as he sets his sights on dominating the Mediterranean. Ruthless and ambitious, he will use every advantage at his disposal to rise to the top. From the heights of Athens to the streets of Rome, alliances will be forged, rivals crushed, and a new empire built from the ashes of the old. In a chaotic time full of treachery and power struggles, only the strong survive.Dont read yet the novel is a complete mess it will be fixed by the day after tomorow give it a try by then.

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.