The Man from Hell - Chapter 29: It’s My First Time. How About It?

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

A broken man who ended his own life finds himself reincarnated into the game he used to play. However, instead of becoming the protagonist or a powerful antagonist, fate places him in the role of a minor villain—a mere stepping stone for the protagonist in the game's first arc.

Su Changqing reincarnated into a fantasy world, directly starting with a heavenly advantage, being born into a Great Emperor family.His father is Su's contemporary family head at the quasi-emperor peak, his mother is the sword pavilion's legitimate daughter with Great Saint cultivation, and even a steward of the Su family is a Saint King.Born into such a powerful family, Su Changqing could easily reach the peak just by doing nothing.But his father, Su Nan, was afraid that his son would become a pompous and arrogant wastrel in such an environment, so he established a Truman World for Su Changqing!In a poor family, with no way to cultivate, Su Changqing struggled through hardships and finally joined a small sect.What he didn't know was that his enlightenment teacher was actually the contemporary Confucian Immortal.The taciturn elder teaching him Sword Techniques was actually the Sword Fool famous across the continent.The irritable elder who always blew up the alchemy furnace was known as the Pill Saint.To prevent Su Changqing from being arrogant due to his talents, many famous teachers were extremely harsh, and the Divine Techniques taught were very difficult to master.But soon, these teachers were all panicking.“Sword Fool master, the Nine Yang Sword is too simple, is there any other Divine Technique?”“Pill Saint master, don't leave, I've already mastered the Yin Yang Reversal Alchemy Technique, teach me something more powerful.”“Hey hey hey, Confucian master, don't run, I've finished reading the books you asked me to...”Looking at the retreating masters, Su Changqing sighed helplessly,“A small sect is really a small sect, unreliable...”

This legend tells the tale of the protagonist, Kuroki summoned to protect the demon king from the hero.

Kuroki, unbeknownst to him, suddenly came to another world. He was summoned by the demon king, Modes. The territory which the demon king overrules was in the midst of being destroyed because of the hero. He had no choice but to bow before Kuroki.

“Please save us, Savior Dono!”

Kuroki nodded, deciding to save the demon king due to an unexpected turn of event.