There's a Madman Sharpening His Knife at Night

Suddenly, a madman sharpens his knife at night, and the emperor's star flutters high.
From now on, there is no need to worry about killing people.
kill! kill! kill!
War disaster, drought, famine.
The protagonist travels through time and becomes a disaster victim at the beginning, in order to survive.
He sold himself to death in the battlefield!
The flower of killing blooms!
Magical powers, martial arts, visualization, breathing...
Rising from the slaves, heading towards the sky.
Along the way, there is a mountain of corpses and a sea of blood behind you!
And gradually, he slowly discovered that the world is not as simple as it seems on the surface.