Rebirth Begins with Rejecting my Childhood Friend - Chapter 404 - On a Business Trip with the Beautiful Secretary.

“Obtaining the topmost degree of talent in sword arts in the world requires giving up 72 years of lifespan, which leaves you with only five more years of your life. At the same time, you will never be able to feel love, kinship, and friendship, and you’ll end up leading a lonely life until your death, unable to procreate, or to have any descendants.

“From now onwards, everything related to happiness in the human world shall no longer be of your concern. Are you willing to accept this?”

“Hahahaha, I’m already alone bereft of all support, my hopes dashed to pieces, shouldering only absolutely irreconcilable grudge and hatred, why would I disagree? Why would I not want it? I couldn’t ask for anything better!!”

His sword sweeps across the Divine Continent for seven days and nights, moving 90,000 miles through the starry skies, unhindered.

He slays saints and buddhas in Heaven, slaughters demons and devils in Hell, sweeping away all the grievances in his heart!

- Description from Novelupdates

A High School Boy without friends, Odamori Tooru reincarnated into a Fantasy World after a bus accident on a School Field Trip. The job that was drawn 『Slavemancer』a Cheat occupation that dominates the minds of other.

As we all know, there is a force that must not be messed with in the Southern Region, thatched cottage.

Among them, the eldest disciple is the Qingyun Sword Master of the Southern Region, with a mastery of swordsmanship.

The second disciple, the Eternal Empress, leads an era.

The third disciple is a great Confucianist in the world, and the star of Wenqu came down to earth.

The fourth disciple, the reincarnation of the demon god, suppressed Jiuyou.

…

Lu Changsheng: Me? I am nothing special, just their master.

- Description from novelbuddy

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.