MTL - Asking About Longevity - Chapter 643 dead line

“You will suffice.”Raizen heard those words the night something chose him to survive.He doesn't know what whispered inside his head. He doesn't know why. But ever since that night, his life hasn't been entirely his own. Something marked him.Now he walks a beautiful world built on even prettier lies, where Eon turns desperation into miracles, Luminite weapons twist the laws of what's possible and what's not, and where humanity has been fighting creatures of shadow - Nyxes - for as long as anyone can remember. Though sometimes, the cruelest of enemies aren't made of darkness at all...But Raizen is starting to realize: the monsters aren't the only things hunting him.Something primordial is watching. Waiting. Pulling strings he can't see.If he wants to survive, he needs to get stronger.If he wants answers, he must become someone even the nightmares fear....But to win?He may have to end anything in his path - and pray he doesn't give the whisper exactly what it wanted all along.

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

Intellectual Villages are old fashioned rural villages recreated with cutting edge technology. Those villages attract the Japanese monsters known as Youkai.

The high school boy Jinnai Shinobu lives in one of those villages and has a Zashiki Warashi living in his house. He tends to run across Youkai with unnerving frequency and this often leads to trouble for him.

The world is terrorized by the powerful Black Witch who has been sealed in the moon. Every ten years, the night of Hexennacht arrives and a chosen witch must battle the Black Witch in hopes of finally defeating her.

As the current decade’s Hexennacht approaches, a mysterious girl named Kagami Kagami arrives and meets Horinouchi Mitsuru, the daughter of the previous Hexennacht representative.

It takes place between Kyoukai Senjou no Horizon and the City Series, two other series by the author.