Void Reaper: The Essence Apocalypse - Chapter 13: Not everyone uses what they were given between their ears

Athen had always lived a solitary life, as without any family or friends, he struggled to survive in his poor, forgotten hometown. The only escape from this grim reality came in the form of tales of magic told by rare visitors from the distant capital.That was, until one day, Athen discovered that magic wasn't just a dream. It was within him.With his newfound power, Athen completed a desperate heist, stealing a priceless diamond. But his triumph was short-lived when he realized the diamond was a fake.Yet... what seemed like a cruel trick turned out to be a blessing in disguise, for the fake diamond held the key to unlocking Athen’s greatest desire: the chance to truly learn magic.

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 –

“Primum non nocere.”