MTL - Escape from Marriage 100 Days: Sweet Wife Steals a Treasure - Chapter 507 Can only die in my hands

The king of assassins was reborn, mastering both alchemy and poison. Sitting inside the space, there was a ghost that loved crying.

The journey to the martial peak is a lonely, solitary and long one. In the face of adversity, you must survive and remain unyielding. Only then can you break through and continue on your journey to become the strongest. High Heaven Pavilion tests its disciples in the harshest ways to prepare them for this journey. One day the lowly sweeper Kai Yang managed to obtain a black book, setting him on the road to the peak of the martials world.

- Description from novelupdates

Once upon a time, a hero had been summoned to a different world in order to defeat the demon king. After the war stretching 3 years ended the commendable hero slew the demon king. And he was forcibly deported back to earth after being dismissed.

Such bullshit!

Elves in addition to beast race, dwarfs and demon race. Even though I wanted to make a harem in the different world I saved! My dream will not come true on earth, where there is no magic at all. Thus, the hero returns on his own. Without the blunder of being extradited to earth this time, he will build a harem of his own in a different world.

Liola—the best assassin in his world—has vowed to kill no more. He was being chased by an assassination organization when he accidentally dropped into a parallel universe: through a dimensional gate and into poor teenager Kaiser’s apartment. Instead of going to the government shelter for lost dimensional travelers, Liola and Kaiser wind up going to school together.

Liola has been trying his best to live the life of an ordinary person, but after certain things happen one after the other, he begins to realize that being an ordinary person could be harder than being an assassin.