His Contractual Mistress - Chapter 18: Result of Being Heartbroken?

Leon and his father, Artorias, are the last remaining scions of a once powerful and illustrious family of lightning mages. After barely surviving an attack that destroyed their home fifteen years ago, they now live in the dangerous Northern Vales, a desolate wilderness far away from civilization. But those who want them dead are strong, patient, and relentless, and it is only a matter of time before they find the two they seek...

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 –

Untolerated by heaven, a boy was restricted by the most powerful spell.

He accidentally acquired a painting inhabited by nine souls that claimed to be immortal.

Then, the legend of a strong young man who violated heavenly principles against the course of nature began.

- Description from Novelupdates

In a world where six once-allied nations now stand divided, the kingdom of Myralis, a symbol of self-sacrifice, has fallen into oblivion. Centuries after its mysterious downfall, Caelum, the last disciple of a forgotten deity, embarks on a perilous journey to restore his nation's honor.Guided by the enigmatic teachings of his vanished mentor and armed with the legendary Seal of Abnegation, Caelum must navigate treacherous politics and face champions from rival kingdoms in a deadly tournament that will decide the fate of the world.As ancient secrets resurface and alliances crumble, Caelum discovers that every truth hides a lie and every ally could become an enemy. His quest could either unite the Six Nations—or precipitate their destruction.Will he master his heritage and fulfill the prophecy that marks him as Myralis’s savior, or will his choices doom the world to chaos?