Well the other day I found a novel on novel updates and must of forgot to add it to my list. All I remember from the description is that cultivators hire people to be targets, and use them to test their strength. Our MC is one such target, but one day gains a cultivation technique where he gains strength by being a target. I can't remember the exact details, as I didn't even read the first chapter. As such I can't remember the name of the MC or the novel, I can't even remember if it was Chinese or Korean.
I read it yesterday i think. In the first chapter 5 peoples brain is destroyed by devil and super awesome guy comes to kill the devil. The devil is the daughter in law of mayor after her death her flesh merges with MC