MMORPG: Rebirth of the Legendary Guardian - Chapter 545: The Return of Dusk Phoenix

When an S-class elite assassin-raised captain of a special ops suicide squad comes home from a high-stakes Africa mission, he finds himself offered something that could potentially set him up for life- a curious assignment that he could use to finally exit his days of war and slaughter.

A man was transported to Ancient China and eventually became a servant of a declining household without a male heir. He utilized his wits and modern knowledge to help the household and eventually become trapped in the sea of political turmoils of the period.

- Description from Novelupdates

The world is governed by the Seven Legendary Heroes, their authority absolute and unchallenged even by their own descendants. They manipulate the world and its people according to their whims.Jonan, son of one of these legendary heroes, discovers his affinity with crystals and mastery over flames, yet lacks skill with weapons, which brings shame upon his family. As he delves deeper into the dark secrets connecting the heroes' power to the rifts and an ancient evil lurking, waiting for the right time, Jonan must move forward with unwavering determination.