Tale of the Red Dragon Without Dragon's Might - Chapter 448 - 440: What do you think this is?

Usami is a beautiful classmate with good morals and top grades. At school, she views Sakuto as her rival. But when he bumps into her after school, he sees a different side of her. She was playing at an arcade after classes, and she had this innocent smile that one couldn’t imagine on her at school.For the sake of getting along with her, he gets close to her at school and then plays together with her after school. They each have their places where they can deepen their bonds, and at last…This is the start of a heart-warming love triangle romcom!

Collection of short stories.

- Description from Novelupdates

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

I was a genius in the Earthen Plane.