The Illegitimate Flame: Bride of Ashes - Chapter 18- unforgivable

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

After I defeated the Demon King, I was executed for false accusations by the heroines.When I came back to life, this was the first thing they said.“I know it’s shameless, but would you help us one more time? Without you, the world will be destroyed.”…Would you help them if you were in my shoes?

Demons, devils, ghosts and monsters

Plunge the mortals weak in horrors;

Arms of gods and blades of devils,

Shroud the world in untold evils.

Lu Sheng was an ordinary civil servant in the modern world. After waking from a drunken stupor one day, he found himself trapped in a dangerous world where demons, ghosts and supernatural monsters terrorize the land.

In this world, ordinary mortals live in dark fear and helplessness, without any means to fight against the supernatural.

As Lu Sheng struggles desperately for survival, he stumbles upon a game mod he had designed for a mobile phone app in his previous life. It unexpectedly becomes his special ability, which enables him to instantly level up any skill he learns, albeit at a cost.

Thus, Lu Sheng begins his journey, striving for power beyond the reach of a mortal as he treads the way of the Devil…

- Description from Novelupdates

Kiyoshiro Takeda lived a life without purpose, drifting through his days with no direction. But one fateful moment changes everything. Now, he finds himself in a world unlike any he has ever known, given a role he never asked for. A new life, an unknown destiny, and a looming catastrophe that only he can prevent. But can someone who failed in his old life truly become the last hope?