Ichiban Ushiro no Daimaou - Volume 13, Chapter 4 — Countless Universes

In the early world of immortal cultivation, there was no physical cultivation among immortal cultivators. And a top bodybuilder who came from the earth has opened up a new path here and became the ancestor of physical training.

- Description from novelbuddy

Qi Condensation. Foundation Establishment. Core Formation. In the current world, only these three realms are known to be achievable. Nascent Soul is but a legend and the realms above it lost to the the long river of time. The modern era is known as Cultivation Civilization, a balance of power and civility, excess and moderation. While cultivation remains a secret practice, it has long since exposed itself to the mundane world, quietly intertwined with each facet of society. While the world appears to be at peace, what lies underneath is a conflict between human, cultivator, and demon, brewing for ages and waiting to implode. Yet in the wake of humanity’s rapid industrialization, qi—and consequently cultivation—is dying.

Being sucked into a fantasy world that nobody leaves doesn't sound half bad to Cain. He was a high school dropout with a drinking problem, living off disability due to his poor health, so it's not like he had much to lose except a few faithful friends he didn't talk to enough.

After a long night of drinking, Cain wakes up looking at what he believes to be the character creation screen of one of his beloved virtual reality games, but with no recollection of having purchased it. His unwitting choice to use the Random Character Creation option, unaware that the choice would be irreversible, sends him into this new world as a Puppet Master, a Summoning based class nobody else in the starting zone has ever heard of.

But as he soon realizes, this is no game, him and hundreds of others have been brought to another world with no instructions, no clear goals and no way home. It's a second chance to live a good life, but what will Cain be able to make of it?

Of the ancient gods only one remained in the world. This god lived alone for thousands of years and no longer had any desires. Legend had it that during the great war between the worlds he used his powers to turn the tide managing to seal the cataclysmic rift bringing order back into the three realms. Time flew by and hundreds of years passed in the blink of an eye.