MTL - Shoujo Grand Summoning - ~ 537 Fifi, Ice Spirit, Bixi!

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

At just four years old, Ryosuke Hyuga trains relentlessly in the Hyuga clan courtyard, sweat dripping from his brow and determination burning in his eyes. Once a member of the oppressed branch family, Ryosuke was destined for the curse seal and a lifetime of servitude to the main family. But fate had other plans.Reborn into the world of Naruto, Ryosuke awakened the Byakugan at birth — a feat unheard of even among the Hyuga. With his rapidly advancing eye techniques and innate talent, the clan hails him as a once-in-a-generation prodigy.Hyuga Hiashi, the clan head who temporarily adopted him, watches his progress closely. The moment news arrives of his newborn daughter's birth, Hiashi makes a shocking declaration:“From this day forward, you are the future husband of my daughter, Hinata. You will marry into the Hyuga main family.”No cursed seal. No servitude.Ryosuke will rise — not as a pawn, but as the shadow behind the Hyuga's future.

In the dawn of existence, the cosmos was a silent, empty canvas until the Mighty Celestial breathed life into the void, scattering seeds of creation across stars and planets. But from the shadows emerged the Anti-Life Entity—a ravenous parasite, the inverse of all design, consuming every living thing in its path.To protect the last bastion of life, Earth, the Constellar Entities, rulers of the grand design, were dispatched. These powerful beings, accustomed to cosmic command, found themselves with an “unacceptable” mission: guarding humanity. Among them, Triangulum, weary of this mundane task, plots his reincarnation. He has amassed forbidden knowledge, weaving a spell to shatter Earth's protective shield, inviting the very forces they were sent to repel.Yet, every move is anticipated by Orion, the Constellars' master strategist. Though they cannot wield their true power without a human conduit, Orion chooses Xerxez as his mortal vessel. Together, they confront Triangulum's dark magic, but the threat deepens when Xerxez's own son, Maximus, becomes the unwilling host for Draco, the Constellars' most formidable foe.Now, Xerxez faces an impossible choice: how can he defeat a cosmic evil when it wears the face of his own son?

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 –