Toaru Majutsu no Index: New Testament - Volume 3, Prologue: In the Fiftieth State. Crisis_of_Blue_Ocean.

The unprecedented magician who will eat all the magic books of the world has appeared.

System, “You have a sickness. Moreover, you’ll have one in every world.”

Hao Ritian, “…”

System, “What’s wrong? Is there a problem?”

Hao Ritian smiled, “No, there’s no problem. I was just a bit excited.”

System, “…”

That smile intensified the system’s feeling of ominous foreboding. It has had this premonition since it learned the name of its host. Now it only prays that this is all its imagination!

Ps: Protagonist shou 1v1, the gong is always the same person.

- Description from Novelupdates

Marauders shot Yuan in the head and buried him in a ditch. They thought it would be enough to put him down. They were wrong.Rising from the dead by the will of the Gun, demigod of revenge and firearms, Yuan only has one goal in mind: track down his murderers across the Unmade World and slaughter every last one of them. With the bullet-core stuck in his skull marking him as a Gunsoul, he can finally teach these arrogant cultivators a lesson they’ll never forget.But revenge isn’t so easy to claim. To carve out a path through the wasteland, Yuan will have to face power-hungry sects, nuclear cultivators, and weapon-gods. Let them come. No one will bury him again.He’ll give them all a taste of Bullet Hell.

The youngest princess of the country of Stellaus, Marietta, was betrothed in a political marriage to the General of the great militant country, Oltaire. General Belvant was often said to be strong, a fierce and terrifying god of a warrior. On the other hand, Marietta was a delicate flower of a princess. Everyone felt pity for poor Marietta’s situation, however, the truth was that Marietta found the General very dreamy… The story of a 30-year old General with a scary face (who was actually quite nice), and the tiny and adorable 18-year old Princess in their times of conflict and of lovey-doveyness.