I have Immortality In The Cultivation World - Chapter 581 - 423: In the Palace Garrison_2

500 years ago, Chen Xi was devoured by a crack in the void and was transported into a cultivation world.

500 years later, he returned back to Earth after enduring through several hardships and discovered that only 5 years had gone by.

…

In the courtyard, beauty at the side, a candle flame wavering.

A gush of clear wind, half a full moon, the peach tree remains unchanging.

…

Wait, whose kid is this?! Why is she calling me papa? Gazing at the little girl in front of him with skin as pale as jade, Chen Xi froze.

…

　
Returning home from cultivation, starting as a stay-at-home dad.

In this life, not fighting to be a king nor claiming to be a tyrant, only praying to peacefully be a wife-pampering mad devil and a child-protecting daddy!

- 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.

[Adapted into Manhwa]In a world teetering on the brink of annihilation at the hands of the primordial evil, Erebos, five heroes rose to challenge fate. [The Brave] Arion. [The Divine Blacksmith] Dweno. [The Nebula’s Progenitor] Luna. [The King of Wisdom] Lisinas. And finally, me, [The Hero of Beginnings] Kyle.After my reincarnation, I found myself hailed as a great hero. “Except for one small detail, nobody mentions me.”At the Hero Academy, where the sacred gift bestowed by the gods, the Hero Record, chronicles the deeds of legends, I enrolled to uncover the truth behind my forgotten legacy.“Fine, then. I’ll just go there and become the top student. No big deal.”

Son of a bitch! I just finished this godawful fantasy novel, and now I'm knee-deep in it – as David, the disgraced son of the Solarian Empire's top general! Talk about some twisted cosmic joke. But hold on a damn minute... maybe this isn't all bad. Armed with the knowledge of that trashy plot, I can become the ultimate shadow player, an overlord perhaps. Screw the damsel-in-distress harem too – it's time to pull the strings and become the real power behind the throne. This isekai might be a steaming pile, but I'm rewriting the ending with a little more... Debauchery (wink wink).