Winter Swan - Chapter 147:

In a world of Mana Awakened powerhouses, Damian Bloodbane awakened into the Legendary, never-seen-before and utterly shameful E-Rank.E-rank.Before Damian Bloodbane, D-rank was the lowest Grade among all of the Mana Awakened in the entire world.After Damian Bloodbane, the world had its first and only E-rank Mana Awakened.It was worse than being Unawakened.The scorn, the ridicule, the mockery, the sarcasm and the utter humiliation he had to go through nearly drove him mad.Until one day…[Death Energy Detected… Absorbed][Necromancer King System Activated][Welcome, Damian Bloodbane, Sovereign of Death][You may select your class][Available Classes:][Death Necromancer][Death Knight][Death Assassin]Witness the rise of Damian Bloodbane from the Legendary E-Rank Trash to be the World-Strongest King of Necromancers! Or… will he?

The dawn era after the end of the half century has gradually rebuilt the order, abandoned civilization, and is full of undivided violence and desire.
The noble and powerful pioneers are in charge of the city, and the evil and mad plagues are in the wilderness.
Pure human beings who cannot mutate are the weakest, dominated by the rulers of the pioneers, and are not as good as animals in the wilderness.
A purely humanized young man with a worldly experience has quietly entered the WTO, holding a three-foot long knife and a long-distance desire to boil in the world of purgatory. From the nameless name to the sorrow of the Supreme Court, the name of the black ride is resounding!

- Description from Uukanshu (translated)

In regards to the MMORPG Cross Reverie, Sakamoto Takuma boasted an overwhelming strength that was enough for him to be called the Demon King by the other players. One day, he gets summoned to another world with his appearance in the game. There, there are two people that insist “I am the real summon master.” Takuma gets slave-turning magic used for summoned beasts cast on him by the girls –

A young man who had longed for stories of good and evil since childhood lost his life in a tragic accident and was reincarnated as a boy named Chrono Mak in another world.

He learned that in this other world, there is magic and witchcraft, and depending on how you train them, you can become as strong as you want to be, so he decided to become the strongest demon king in order to recreate the story of justice and evil he once dreamed of.