Jitsu wa Ore, Saikyou deshita? ~ Tensei Chokugo wa Donzoko Sutāto, Demo Ban'nō Mahō de Gyakuten Jinsei o Jōshō-chū! - Chapter 39 - Creature named sister

Ethan possessed everything one could desire, wealth, happiness, luxury cars, and a loving girlfriend.He had never fought a day in his life, but then suddenly, he woke up in a different world.A world were destruction and bloodshed was the norm. A world where the weak had no place to survive.Ethan now possessing the body of a boy who had failed his awakening twice and was on his last try, now stood in this world.Can Ethan who never fought a day in his life survive in a world where battles and death occurs every second, minute, hour and day.Would he rise through the ashes of the world, or would he burn with it.

In the vast Marvel universe, where superpower was still slowly growing in its infancy, several peerless superheroes tried to find their path in The Marvel Universe. A young adult named Ron from modern Earth unwittingly stumbles into such a world and begins his journey with an unknown power. This is a magnificent yet unknown true marvel world! This is the story of a normal young adult and his adventures!

- Description from Novelupdates

Beings that create and control monsters and demons, beings that build and reign over malicious labyrinths, the chosen individuals to possess an overwhelming Unique Skill… They are the Demon Lords.

Originally born from a wealthy family, she ends up leading a vagrant life for fifteen years. However, when she is eventually found by her family, she falls into another devious plot and eventually dies tragically.