Kill Me More Times, I'll Become Invincible - Chapter 288:

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

15 years ago the world discovered magic as well as mythical beings (basically beings from various legends) in another dimension. Humankind learned to summon these dangerous mythical beings and use their power to great effect. Seven countries formed contracts with these “mythical beings” and gained their allegiance as a result. The mythical beings will choose their summoners on their 14th birthday and give them a stigma. Schools have been set up to train summoners and magical swordsman (basically bodyguards that give the summoners time to cast their spell) as a result.

15 years later after the finding of magic Kazuki Hayashizaki is chosen as a summoner and given a stigma to indicate that. This is surprising since males aren’t chosen as summoners due to their low amount of mana compared to females. As the first male to be a summoner Kazuki is under a lot of scrutiny by almost everyone.

To complicate matters his sister (who’s a magical swordsman) is against him going into summoner school to train there as a summoner. Because summoners and magical swordsman have a cat mouse thing going on where summoners look down on magical swordsman as inferior so his sister naturally is against him going there. She’ll stop him even if it means going to war.

Kazuki however is determined to thrive in summoner school and has already determined to give it his all. Even if he’s the lowest ranked student (ranked E) and his fellow students intend to demean him he’ll prove himself as the strongest summoner.

The salaryman who had a dream of becoming a CEO has finally succeeded.

However…

There was no one. No one was around to celebrate his success. Then on his first day of work, news of the death of a former colleague that he had laid off came. Additionally, his family left him, who was only concerned about the company.

The life he thought was right crumbled right in front of him. Where the heck did it all go wrong? Then, another opportunity came for Han Yoo-hyun, who had plunged down into despair.

This time, for sure. He was going to live properly. He was going to change it all with his whole being. The new life that Han Yoo-hyun was creating.

That valued life that will outshine any other is unfolding now!

Regaining the memories of his previous life, Cyril realised that he was an otome game’s character, the villainous daughter– Sophia’s butler.At the rate things were going, Sophia would eventually have the prince stolen away from her by the heroine, fall into darkness, and be executed.Wanting to save the villainous daughter he was so fond of, Cyril moved to eliminate all the factors that would cause her to fall into darkness, raising her up to be a talented and beautiful girl who could win the prince’s love, however…