Extra's Harem: Invincibility Starts with Marriage and lots of Children - Chapter 1 - - An Extra’s Life: Twist (1)

When a fantasy kingdom needs heroes, they skip the high schoolers and summon hardened Delta Force operators.Lieutenant Cole Mercer and his team are no strangers to sacrifice. After all, what are four men compared to millions of lives saved from a nuclear disaster? But as they make their last stand against insurgents, they’re unexpectedly pulled into another world—one on the brink of a demonic incursion.Thrust into Tenria's realm of magic and steam engines, Cole discovers a power beyond anything he'd imagined: magic—a way to finally win without sacrifice, a power fantasy made real by ancient mana and perfected by modern science.But his new world might not be so different from the old one, and the stakes remain the same: there are people who depend on him more than ever; people he might not be able to save. Cole and his team are but men, facing unimaginable odds. Even so, they may yet prove history's truth: that, at their core, the greatest heroes are always just human.

Yun Woo is the youngest author in history to enter the literature world. His debut work was a massive hit but this success was short lived for the unprepared.

A failed investor from 2017 got drunk and woke up in the 1980s. China is just opening up, and the economy is blooming. There is also the dissolution of the Soviet Union, the bursting of the Dot-com bubble and other financial crisis. He used his knowledge of the future and slowly build up his empire.

- Description from novelupdates

[Pre-Author's Note: MC develops as time passes, it starts out slow but surely]“The Apocalypse isn't just fit for anyone... Without Strength, you're just a tool waiting to be exploited, So hurry the fuck up and get some strength already,”The world ended in an instant.One moment, Simon, a 20-year-old game designer, was sitting at his desk, immersed in code.The next, the sky cracked open and monsters poured into the streets.Werewolves with claws sharp enough to slice through steel.Undead skeletons that marched with deadly purpose and Zombies that infected humans with the power of their bite.The gods had unleashed an apocalypse, and humanity was no longer at the top of the food chain.Simon ran, he survived... and then he was granted a power.|Congratulations You have been binded to the Vampire Overlord System|He was something else.A vampire overlord.Yet the Apocalpyse had only just begun...