Harry Potter: A Certain Ancient Rune Professor of Hogwarts (TL) - Chapter 718

How long can one ignore the voices in their head?Nine years. To Mark, that was the limit.For the majority of his life, Mark White has been fighting a constant battle for his sanity. The voices in his head pushed him toward madness one whisper at a time, and the music he used to ward against them was gradually losing its effects.As his mental state slowly deteriorated, Mark spent more of his time working on a game he had been developing and lamenting his lack of romantic experience.One night, the voices dealt him a powerful blow, bringing their battle to an end. To his surprise, Mark won the battle, but that came at a great cost.The voices might have disappeared, but a visual hallucination arrived to replace them, taking the form of a character from his game: Maids VS Apocalypse. Little did he know that the real apocalypse was already coming for him.

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

Lin Jin never imagined he would ever transmigrate. And to such a peculiar world at that. Here, deadly beasts were regarded as sacred, and thankfully, he owned a museum for deadly beasts.