Mecha Battle: Why Do You Use Body to Destroy Stars? - Chapter 44

When the eldest prince Luo Fei reached 18 years old, the database automatically screened the genes of omegas across the entire empire for matching. The only son of a wealthy businessman, Mo Lin, had a gene match of more than 90% with the eldest prince. However, the moment he saw Mo Lin, Luo Fei learned that this omega is a sick child with paralyzed legs, hemiplegia, and severe mental illness???

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