Sending the Groom to Jail on My Ex-Girlfriend’s Wedding - Chapter 27

Lin Xiao was an orphan who strived to get stronger while living with his sickly younger brother in an unnamed small village.

This book was inspired by My Hero Academia: Adaptation“Who decided being quirkless means you can't be a hero? Those are just rules made by people who never tried to break them.” When a battle-hardened warrior dies in one world and awakens in the body of a quirkless boy in another, the rules of heroism are about to change.Armed with combat experience from a darker realm and an iron will forged in warfare, he sets his sights on U.A. High School - the pinnacle of hero education. But in a society where superpowers are everything, his approach to strength might just shatter the entire system.Behind a gentle smile lies the mind of a warrior. As he builds his power through unconventional means, one thing becomes clear: rules were meant to be broken, and this world's definition of “hero” is about to be rewritten.Sometimes the strongest ability isn't a quirk at all. It's the will to change everything.

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