MTL - Tome of Blood - Chapter 272 -122-Rolling

Humanity’s home is no longer Earth. Intersellar travel is now a common occurence, and technology has replaced blood and flesh.Luka, who grew up in the slums, has turned fifteen and taken the selection exams. His aptitude is of the “Imperial Guard.”

What was originally an ordinary day, suddenly became a historical turning point. Enormous, mysterious Cubes appeared all over the world without warning and as if Judgement Day’s spears, inserted themselves into the blue planet.

From inside the enormous Cubes, endless streams of monsters gushed out alike raging tides, utterly defeating the unguarded armies of each state in the blink of an eye.

In order for humanity to preserve its final embers, the heads of states issued orders of retreat, to no longer attack the Cubes but rather to cling to remote cities, which they turned into self-sufficient survivor bases and around which they built 100-meter-tall Walls of Life!

Many years later, while bearing the heavy weight of history, the first expeditionary force brought back a world changing piece of information. The Cubes possessed exceedingly high intelligence and they regularly transmitted mission instructions to humans nearby. The mission rewards were incredible.

Since then, humans rushed out of the confines of the walls and once more set foot on the wasteland!

- 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.

An engagement paper to lock one’s destiny. With her family facing financial difficulties, she marries into the family of the richest man in Qingzhou as his wife. Her Mother-In-Law’s doubtfulness; her husband’s childhood sweetheart; her mean elder sister-in-law; her narrow-minded younger sister-in-law… Being inferior, Sang Wan withdraws without a choice. As time passed, she ended up being lonely and died tragically.