Toaru Majutsu no Index: New Testament - Volume 16, Chapter 1: Securing Safety in the Scorching Heat - Water_Hunt.

Thousands of years ago, the great abilities of the three teachings of Buddhism, Daoism, and Demonism decided on a place for becoming immortal. Three thousand years ago, a Taoist was close to becoming immortal. Three hundred years ago, the Daqian Dynasty was established, and chaos is expected in another three hundred years. In this era, the path to immortality opens; a celestial swordsman freezes fourteen states with one sword, a heavenly Daoist maiden seeks eternal life, a naturally born Holy Son claims to be invincible, and a Buddhist Holy Monk saves all sentient beings.Gu Wen lives as a beggar, enters a household as a servant, witnessing the disordered world, drifting aimlessly.In a world filled with divine beings, he alone is a mortal.However, a lowly origin is not a disgrace; striving through the grand path, even as a common man and mundane son, he can still be the foremost in the world.“Mortal Gu Wen, my Dao is euqaling the heavens!”

Yang Qing never expected that he would travel to the fairy world, let alone that he would have a chance to travel back.

It’s just that after I came back, I found out that this world is not friendly to cultivation, and it’s a completely degenerated world, so what else can I do?

Part-time work is not allowed, so he can only rely on the rune technology of the fairy world and develop a little black technology to live his life, so his eyes are directly fixed on the moon above his head, where his dream begins!

- Description from novelbuddy

Bai Xiao descended, lifting his head to not only see the bizarre and magnificent world but also the professional modifier he had downloaded before crossing over.“Drain all experience from my sub-occupations, 'Biological Mecha Master', 'Mystic Explorer', 'Special Hypnotist', transforming it into one million potential points, all enhancing my main occupation, 'Fighter'!”“I... have obtained the golden ultimate occupation, 'God of Martial Combat'!”The largest urban agglomeration in the world, a night of torrential rain.On the ground, countless Killing Ghosts and Fighters fought to the death, while hordes of metal Mechas and Biological Armors exploded and self-destructed. Blood and flame intertwined, plunging everything into primordial violence and chaos.Atop a high tower, Bai Xiao stood silently amidst the rainy darkness, like a stiff and terrifying statue. His crimson eyes looked down below, restrained yet bloody, cold yet hiding madness.He leaped down with his trench coat wildly dancing.The God of Martial Combat descended upon the final battleground!A cold voice echoed across the city skyline.“Next, I will kill everyone present! If you have the ability, try to stop me...”A modern city of extravagant luxury, an era of entertainment and consumption supreme.Beneath seventy years of peaceful façade, lied another mad and bloody Inner World.Fighters, masters of their martial traditions, and Killing Ghosts, controlled by combat modes, engaged in a frightful, relentless slaughter.Metal Mechas with terrifying energy and Biological Armors extracted from monstrous cells commenced a brutal struggle between old and new technologies.In this era infested with machinery and altered by external entities, to proclaim the power unique to humans might be an unimaginable romance...

What should I do after passing through?

Mo Jun’s answer is:

Life will be meaningless if you don’t work hard to enjoy it.

Then play music, then dance.

(Note: This book is a colleague of Qin Shimingyue, classified as light novels, not historical texts.)

- Description from novelbuddy