MTL - Steel Shell System - v2 Chapter 296 alertness

Doomsday comes, and human beings enter the heavenly world.
Ten years later, Yang Chen, who was betrayed tragically, returned strongly with the Tianyu bug. In this life, he vowed to make the betrayal pay the price. He has a powerful bug bonus, just like an open hang. Frightened to hear…

- Description from novelbuddy

Rosemary spent 18 years thinking she was a member of the wealthy Harris family, only to discover she was a fake rich girl. When the real heiress returned, Rosemary was cast aside and sent back to her poor hometown. But fate had other plans for her, as she soon discovered that her hometown was actually the most exclusive villa area in the country. In a single night, Rosemary went from a modestly wealthy girl to the true heiress of a top-tier elite family. Her biological parents showered her with love, handing her millions of dollars in pocket money, providing access to any car from their fleet, and letting her buy anything from the world’s top designers. As for school, the best institutions were at her fingertips, and if she didn’t feel like studying, she could play with the family company.But what shocked Rosemary the most was finding out she had an ex-fiancé. She couldn’t understand why he kept clinging to her, holding her hand, and trying to kiss her. “Who are you, sir?” Rosemary asked, annoyed. “Sweetheart, I’m your husband,” the ex-fiancé responded. “I don’t have a husband, only a former fiancé”

This story is centered around the man named Yi Ji-Hyuk, who has spent 1000 years in a Medieval Western fantasy-like world before returning back to the modern-day Earth. When he returns, he finds that his home is facing monster threats, and that humans with superpowers have appeared to protect the innocent people of Earth.