I Became the Demon Lord and my Territory is an Uninhabited Island - Chapter 50.5

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 –

An old MMORPG called Live Dungeon. Before the service was terminated, Kyotani Tsutomu made full use of 5 notebook PCs to clear the game and was invited to a different world. And then, Tsutomu was speechless when he saw a live relay of a dungeon capture in the different world. They bulldozed through without any thought of strategy. The misfortune of getting the healer position. Tsutomu reinstated the White Mage that had always been his favorite in games and aimed to conquer the dungeon to find the key to his escape from the different world.

The extraordinaire has disrupted the silence of the world and ever since then, technology has taken a different path.

Anyone who could construct a stable Spell Model could become a Wizard — that was the Wizards’ ultimate secret! Having been given a new life as the son of an aristocrat and armed with a super quantum computer from his past life, Spell Models came as easily as breathing to Merlin. With this overwhelmingly huge advantage, would Merlin become the greatest Grand Wizard of all time?

- Description from Novelupdates