Tensei Shitara Slime Datta Ken (WN) - Chapter 385

This is a story about a young man who sought to fight against his destiny. With the help from billions of Dragon Energies trapped on the Rising Dragon Pillar in his body, he emerged from the dark and quenched himself with the blood of ancient dragons. He fought the heaven with the Buddhist Art for the people he loved and built the Eternity Kingdom with his own hands. This is a story about the rise of the Martial Emperor who will rule both earth and heaven.

- Description from Novelupdates

Loose cultivator Shi Lang gradually found himself in the realm of invincibility. However, when he finally tried to ascend to the higher realm, the spirit of the world was nearly exhausted.

So, between his ascension to a new world or the well-being of his home, he chose the latter and sacrificed his life to save the world.

Nobody knew what he gave up for the world, and he told no one.

Although his sacrifice had gone unsung, there was still someone who witnessed everything. A treasured artifact he carried on his body preserved his soul and let it escape a tragic end.

Eons passed.

The human race stepped out from the age of cultivation into an age of stellar conquest.

The spirit energy in the world was now scarce, but humans found other means to excel.

In this highly-advanced time, Shi Lang's soul has found a chance to be reborn.

What happens when an ancient cultivator that neared the level of a deity before his first death gets a second chance at life in the space age?

A black pearl brought Jiang Feng from a doomsday stage where top masters with one emperor, two emperors, three emperors, four deities, and seven peerless cities show off their glory to parallel time and space, and this time and space-the end of the world has not yet opened! !! Under the sky, the youth look up, if I have strength, can I get through … these two time and space! !!

- Description from 69shu

I met the male lead in prison.