I'm Not the Mastermind - Chapter 16

The best way to declare war on a spy as an ordinary person is to become a spy as well.As a spy, if you want to go to war with a powerful espionage organization, join an equally powerful espionage organization.If you are unable to join any powerful espionage organization, then establish your own espionage organization and fight until destruction or victory.This is the war of spies, telling the story of how a group of ordinary people achieved extraordinary success.

In this world, orphans or just anyone without any hope for this world can apply to become a “walking target”. Their sole purpose is to be a practicing dummy for the students of the sect who train to become “Demon Hunters”. These students need “walking targets” to test their training on living, walking beings of flesh and blood.
In exchange, they will be provided with food & shelter.
Their existence value is lower than a slave, but if they manage to survive a few years they can receive a life long pension.

Xiao Han is such a “walking target”. One time he witnessed a powerful Demon Hunter disposing a demon. When the demon died, a fragment of the demon that managed to escape entered Xiao Han’s heart. No one saw that, and even Xiao Han himself only felt some discomfort for an instant.

But that thing in his heart soon gave Xiao Han visions, and the first one is of a cultivation method which allows Xiao Han to absorb damage to enhance his body. A perfect cultivation method for a “walking target”.

- Description from Novelupdates

Shaymon, the man who has achieved the apex of dark magic, is framed as being a Demon King and is killed.

(Rebirth + Business warfare + Pampering spouse + Dog food)Investing today? I've got more important things to handle.Financial crisis? Not my problem; anyhow, I won't be losing money.Huh? This stone of yours is pretty nice, wait for a call at home!Xiao Ming closed the door, turned around, and took out a fist-sized diamond: “Honey, let's grind this into a ball for the kids to play with!”