Swallowed Star 2: Land of Origin - Chapter 11 - 10: Flame Wind Pavilion

In short, MC inadvertently created a world, but as the creator of the world, he did not know the world at all. He should have lived here like a fish in the sea with some plug-ins that MCs always have. But now he is even stumped by the bugs in the instant world. Luckily, in this world he has found his shadow guard, or his lover? So the daily adventure is getting not so boring…

- Description from Novelupdates

Yang Qi was the son of the patriarch of a wealthy family from a small town.

Believing himself to be in love, he stole a pill for his lover, only to have the girl betray him, by taking the pill and leaving him behind.

Caught, his dantian was crippled and left to die under the lightning.

This lightning helped him to recover his lost martial arts and also helped him gain a new, divine-like cultivation technique.

After this second chance, he gains more power as he sought revenge and also to find about his missing mother….

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 –

Where there is light there shall be darkness

Hero? Nahh I'm the demon.

In a world where the demons are looked on as the incarnation of evil, the human-demon war raged on across the whole continent.

The Seraphims, protector of humanity, and the Demon lords who rule across all demonkind. Amidst all the chaos, Simon was reincarnated as the lowest ranking demon noble.

A brutal world where the strong feeds on the weak, eat or be eaten, kill or be killed. A demon far off from humanity….a dream unfulfilled in his previous life will be achieved in this life. Taking on the moniker of Laplace, he destroys all his enemies and rise over them.