MTL - The City of Terror - Chapter 2 , slugs?

[The Demon King is Dead], a story in which the Demon King got immediately killed in the Prologue. I became the ‘Demon Prince’ of said novel.

…Help me.

In the end, war couldn’t be extinguished. But, there was a transformation. Even in the heart of a worthless accomplice in murder who was indifferently continuing his task, there was a transformation. The massive weapon “Object”.

This was a weapon that changed the whole definition of war. An exchange student named Quenser, who was dispatched to the battlefield, met at the base a girl with a strange aura. The girl, dubbed “Elite”, is the pilot of “Object”. The near future. This diminutive boy had come to take on the role of standing up against the strongest weapon “Object” for the sake of the girl. This was the motive for their first meeting.

The little handsome son-in-law passed through a world as waste material and the husband of a wealthy family. But because of his lacking aptitude, the wealthy family had driven him out. So he worked hard and found a more powerful family’s thighs to hold onto. Soon enough, he became the strongest son-in-law and husband in history.

In this world, it was impossible to practice martial arts. It was futile so he might as well take advantage of his wife’s thighs and maintain a comfortable and leisure lifestyle.

He’ll train his wife to become the strongest and best person in the world.

“Whoever dares to provoke me, let my wife kill you!”

- Description from Novelupdates

A man reincarnates in the body of a boy who suffered a tragedy, only to realize that he is in the world of My Hero Academia. What's even stranger is that his quirk seems to have the abilities of Nen and Haki.