MTL - I Was Fed the Fruit by the World Nobles and Became the Fifth Emperor - Chapter 9

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

An alien race invaded the Earth on June 6, 2128. At the midst of this war, many nations allied with the alien threat and the war nearly wiped out the rebelling humans of the planet. At the edge of mankind's survival, the United Nations Army launched its forces to eliminate the immediate stellar threats that loomed over Earth.

General Seeker Carlean, commander and leader of the mission, risked and gave his life to destroy the immediate stellar threat. The battle was won though Earth lay in ruins. Perhaps mankind will live to see a few years of peace before the alien threat returns to wipe out their existence.

At the immediate aftermath of the stellar battle, the fallen Seeker Carlean awakens and finds himself at aged 17, living the peaceful life he lived 16 years before he died.

So begins a new game in the battle for humanity's survival.

I don’t know the length of Hydra, or the depth of S.H.I.E.L.D.

I don’t know that Ant-Man has an outfit, and I don’t know that the Winter Soldier has an iron fist.

I don’t know that there is chaos in the Bliss Space, and I don’t know that Miss Xiaoyu wants to get married.

I don’t know if the walking corpse is cheating, I don’t know whose fault the alien is.

I don’t know the legend of mutants, I don’t know that Kryptonians can’t afford to provoke them.

I don’t know that Black Panther’s family has a mine, and I don’t know that Iron Man is a mess.

I don’t know what happened to Lei Shen’s family, and I don’t know that Thanos is thinking about making troubles.

He doesn’t know the past or the way forward, he only knows that he stands firm at the critical moment and cannot be cowardly.

- Description from novelbuddy

Side story of Kyoukai Senjou no Horizon bundled with the first press release of the 1st, 3rd, 5th and 7th Blu-ray volumes of both seasons of anime.

This side story follows Asama, Kimi and Mitotsudaira aboard Musashi one year before the beginning of the main story, as Asama is considering to create a music band together with her two friends for the next festival in Aki, a territory under the governance of K.P.A. Italia.